Virtual Journal of Nanoscale Science & Technology

Shape Dynamics and Rheology of Soft Elastic Particles in a Shear Flow

Tong Gao, Howard H. Hu, and Pedro Ponte Castaneda
The shape dynamics of soft, elastic particles in an unbounded simple shear flow is investigated theoretically under Stokes flow conditions. Three types of motionsteady-state, trembling, and tumblingare predicted, depending on the shear rate, elastic shear modulus, and initial particle shape. The ste ... [Phys. Rev. Lett. 108, 058302 ] published .

Mesoscopic approach to granular crystal dynamics

Marcial Gonzalez, Jinkyu Yang, Chiara Daraio, and Michael Ortiz
We present a mesoscopic approach to granular crystal dynamics, which comprises a three-dimensional finite-element model and a one-dimensional regularized contact model. The approach investigates the role of vibrational-energy trapping effects in the dynamic behavior of one-dimensional chains of part ... [Phys. Rev. E 85, 016604 ] published .

Response of the electric conductivity of double-stranded DNA on moderate mechanical stretching stresses

Mario Wolter, P. Benjamin Woiczikowski, Marcus Elstner, and Tomas Kubar
The response of charge transport in double-stranded DNA to mechanical pulling has been studied with a multiscale computational method using classical molecular dynamics simulation, approximative density-functional theory calculations and the Landauer-Buttiker theory. The effect depends on the exact ... [Phys. Rev. B 85, 075101 ] published .

Enhanced downconversion of UV light by resonant scattering of aluminum nanoparticles

Rajeshkumar Mupparapu, Kevin Vynck, Iacopo Malfanti, Silvia Vignolini, Matteo Burresi et al.
Metallic nanoparticles are known to enhance nonlinear optical processes due to a local enhancement of the optical field. This strategy has been proposed to enhance downconversion in thin film solar cells, but has various disadvantages, among which is the fact that the enhancement occurs only in a ti ... [Opt. Lett. 37, 368 ] published .

Effects of pH on Dissolution and Surface Area Loss of Platinum Due to Potential Cycling

Amar Prasad Yadav, Takayashi Okayasu, Yu Sugawara, Atsushi Nishikata, and Tooru Tsuru
By using electrodeposited Pt nanoparticle electrodes, we clarify the relationship between the amount of dissolved Pt and the change in the electrochemical active surface area (ECA) of Pt due to potential cycling. Cyclic voltammetry of Pt was carried out in the pH range 0.44.0 in three different pote ... [J. Electrochem. Soc. 159, C190 ] published .

Oxygen Electroreduction on PtCo, PtCo and PtCo Alloy Nanoparticles for Alkaline and Acidic PEM Fuel Cells

Mehtap Oezaslan, Frederic Hasche, and Peter Strasser
Pt-Co alloy nanoparticles have emerged as one of the most promising electrocatalysts for the oxygen reduction reaction (ORR) in hydrogen fuel cells. Our study presents a comprehensive structural, compositional and electrochemical characterization linked with ORR activity for carbon supported PtCo, P ... [J. Electrochem. Soc. 159, B394 ] published .

Electrically Rearranged Birnessite-Type MnO by Repetitive Potential Steps and Its Pseudocapacitive Properties

Ryota Inoue, Yumiko Nakashima, Kazuaki Tomono, and Masaharu Nakayama
Nickel(II) ions-intercalated manganese dioxide (Ni/MnO) film with a layered structure on Pt electrode was subjected to repetitive steps between anodic (+0.8 V) and cathodic (0.0 V) potentials in different conditions. Current response during the repetitive steps varied drastically, depending on the n ... [J. Electrochem. Soc. 159, A445 ] published .

Modeling of silicon nanocrystals based down-shifter for enhanced silicon solar cell performance

F. Sgrignuoli, G. Paternoster, A. Marconi, P. Ingenhoven, A. Anopchenko et al.
A transfer matrix model of a luminescent down-shifter (LDS) layer, consisting of silicon nanocrystals (Si-NCs) embedded in a silicon oxide matrix, on a silicon solar cells is presented. To enhance the efficiency of the silicon solar cell, we propose using a SiO/Si-NCs double layer stack, as an anti- ... [J. Appl. Phys. 111, 034303 ] published .

Mesoporous MnO and Its Capacitive Behavior

S. Devaraj, G. S. Gabriel, S. R. Gajjela, and P. Balaya
Mesoporous MnO nanoparticles (meso-MnO) were synthesized by a simple and cost effective soft template method. TEM and N adsorption-desorption studies revealed that MnO comprises of mesoporous nanoparticles with grains of 4-5 nm size and pores in the same range. Specific capacitance of 297 F g was ob ... [Electrochem. Solid-State Lett. 15, A57 ] published .

A tapered channel microfluidic device for comprehensive cell adhesion analysis, using measurements of detachment kinetics and shear stress-dependent motion

Peter Rupprecht, Laurent Gole, Jean-Paul Rieu, Cyrille Vezy, Rosaria Ferrigno et al.
We have developed a method for studying cellular adhesion by using a custom-designed microfluidic device with parallel non-connected tapered channels. The design enables investigation of cellular responses to a large range of shear stress (ratio of 25) with a single input flow-rate. For each shear s ... [Biomicrofluidics 6, 014107 ] published .

Formation of a disordered solid via a shock-induced transition in a dense particle suspension

Oren E. Petel, David L. Frost, Andrew J. Higgins, and Simon Ouellet
Shock wave propagation in multiphase media is typically dominated by the relative compressibility of the two components of the mixture. The difference in the compressibility of the components results in a shock-induced variation in the effective volume fraction of the suspension tending toward the r ... [Phys. Rev. E 85, 021401 ] published .

Transmission enhancement in a non-adiabatic tapered nano-aperture waveguide

Yongzhu Chen, Xiangsheng Xie, Yongyao Li, and Jianying Zhou
Transmission enhancement via transverse mode control through an aluminum hollow tapered waveguide with a sub-100 nm aperture is simulated with optical wavefront modulations via a binary optical element. Efficient delivery of an input field by exciting the fundamental propagating mode near the apex i ... [Appl. Phys. Lett. 100, 051104 ] published .

Boundary-enhanced momentum relaxation of longitudinal optical phonons in GaN

N. Ma, B. Shen, L. W. Lu, F. J. Xu, L. Guo et al.
The influence of the channel geometry on the high-field electron transport properties has been investigated in n-type GaN at room temperature. It is found that electrons in narrow channels drift much faster than those in wide channels. This discrepancy is attributed to the boundary-enhanced momentum ... [Appl. Phys. Lett. 100, 052109 ] published .

Newton black films as wetting systems

Pedro Tarazona, Hector Martinez, Enrique Chacon, and Fernando Bresme
Newton black films (NBFs) can appear under a wide range of experimental conditions. NBFs define the adhesive states of foams and emulsions, showing their formation is a very general physical phenomenon. We show that the existence of NBFs and their whole experimental behavior can be understood within ... [Phys. Rev. B 85, 085402 ] published .

Relations between the diffusion anomaly and cooperative rearranging regions in a hydrophobically nanoconfined water monolayer

Francisco de los Santos and Giancarlo Franzese
We simulate liquid water between hydrophobic walls, separated by 0.5 nm, to study how the diffusion constant D parallel to the walls depends on the microscopic structure of water. At low temperature T, water diffusion can be associated with the number of defects in the hydrogen bond network. However ... [Phys. Rev. E 85, 010602 ] published .

Micromagnetic analysis of the Rashba field on current-induced domain wall propagation

Eduardo Martinez
The current-driven domain wall propagation along a thin ferromagnetic strip with high perpendicular magnetocrystalline anisotropy is studied by means of micromagnetic simulations with emphasis on the role of the Rashba field, which has been predicted to play a dominant role in multilayer stacks with ... [J. Appl. Phys. 111, 033901 ] published .

Rolling and sliding of a nanorod between two planes: Tribological regimes and control of friction

Mykhaylo Evstigneev and Peter Reimann
The motion of a cylindrical crystalline nanoparticle sandwiched between two crystalline planes, one stationary and the other pulled at a constant velocity and pressed down by a normal load, is considered theoretically using a planar model. The results of our model calculations show that, depending o ... [Phys. Rev. B 85, 035447 ] published .

Temperature dependence of microwave voltage emission associated to spin-transfer induced vortex oscillation in magnetic tunnel junction

P. Bortolotti, A. Dussaux, J. Grollier, V. Cros, A. Fukushima et al.
The temperature dependence of a vortex-based nano-oscillator induced by spin transfer torque (STVO) in magnetic tunnel junctions (MTJ) is considered. We obtain emitted signals with large output power and good signal coherence. Due to the reduced non-linearities compared to the uniform magnetization ... [Appl. Phys. Lett. 100, 042408 ] published .

Rapidly switchable water-sensitive shape-memory cellulose/elastomer nano-composites

Yong Zhu, Jinlian Hu, Hongsheng Luo, Robert J. Young, Libo Deng et al.
We report a new phenomenon in which the reversible formation and disruption of a cellulose nano-whisker (CNW) percolation network in an elastomeric thermoplastic polyurethane (TPU) matrix leads to an unprecedentedly rapidly switchable shape-memory effect (SME) that may be activated by water. The mat ... [Soft Matter 8, 2509 ] published .

Segregation at a small scale: synthesis of coreshell bimetallic RuPt nanoparticles, characterization and solid state NMR studies

Patricia Lara, Marie-Jose Casanove, Pierre Lecante, Pier-Francesco Fazzini, Karine Philippot et al.
Coreshell small RuPt nanoparticles stabilized by a polymer (polyvinylpyrrolidone, PVP) have been prepared by co-decomposition of [Ru(COD)(COT)] [(1,5-cyclooctadiene)(1,3,5-cyclooctatriene)ruthenium] and [Pt(CH)(COD)] [dimethyl(1,5-cyclooctadiene)platinum(ii)] organometallic complexes at room tempera ... [J. Mater. Chem. 22, 3578 ] published .

Enhanced gas sensing properties by SnO nanosphere functionalized TiO nanobelts

Wen Zeng, Tianmo Liu, and Zhongchang Wang
We report synthesis of hierarchical nanostructures of SnO nanosphere functionalized TiO nanobelts as a novel sensing material by a simple hydrothermal technique. A systematic comparison study reveals an enhanced gas sensing performance for the sensor made of SnO and TiO toward volatile organic compo ... [J. Mater. Chem. 22, 3544 ] published .

Dynamics of fibers in a wide microchannel

Agnieszka M. Slowicka, Maria L. Ekiel-Jezewska, Krzysztof Sadlej, and Eligiusz Wajnryb
Dynamics of single flexible non-Brownian fibers, tumbling in a Poiseuille flow between two parallel solid plane walls, is studied with the use of the HYDROMULTIPOLE numerical code, based on the multipole expansion of the Stokes equations, corrected for lubrication. Fibers, which are closer to a wall ... [J. Chem. Phys. 136, 044904 ] published .

Coherently controlled molecular junctions

Uri Peskin and Michael Galperin
Within a generic model, we discuss the possibility of coherent control of charge fluxes in unbiased molecular junctions. The control is induced by resonances between the Rabi frequency due to a pumping laser field and internal characteristic frequencies of pre-designed molecular donor-bridge-accepto ... [J. Chem. Phys. 136, 044107 ] published .

Modified double emulsion process as a new route to prepare submicron biodegradable magnetic/polycaprolactone particles for in vivo theranostics

Naveed Ahmed, Millan Michelin-Jamois, Hatem Fessi, and Abdelhamid Elaissari
A modified double emulsion evaporation method was devised to encapsulate active ingredients to be used for theranostic purposes. In comparison with classical double emulsion methods, the solvents used for this modified method are miscible. Aqueous and organic ferrofluids having different solid conte ... [Soft Matter 8, 2554 ] published .

High-efficiency inverted dithienogermolethienopyrrolodione-based polymer solar cells

Cephas E. Small, Song Chen, Jegadesan Subbiah, Chad M. Amb, Sai-Wing Tsang et al.
Inverted polymer bulk heterojunction solar cells have received a great deal of attention because of their compatibility with large-scale roll-to-roll processing. The inverted cell geometry has the following structure: substrate (rigid or flexible)/indium tin oxide/electron-transporting layer/photoac ... [Nat. Photonics 6, 115 ] published .

Templateless nanostructuration of polymer surfaces

Juan P. Fernandez-Blazquez and Aranzazu del Campo
The surface topography of different polymer films (polyterephthalates, polyolefins, polyethers) after oxidative plasma treatment has been studied. Distinct surface nanopatterns were observed depending on the polymer type and were characterized by SEM. Their geometry and dimensions at low etching deg ... [Soft Matter 8, 2503 ] published .

Bio-inspired nanoreactor based on a miniemulsion system to create organicinorganic hybrid nanoparticles and nanofilms

Yuuka Fukui and Keiji Fujimoto
We developed a novel route to control both mineralization and polymerization inside a nanoreactor based on a miniemulsion system to create organicinorganic hybrid nanomaterials with diverse structures and morphologies. Nanodroplets of calcium nitrate (Ca(NO))/monomer and nanodroplets of sodium carbo ... [J. Mater. Chem. 22, 3493 ] published .

Micro- and nanocrystals of the iron(iii) spin-transition material [Fe(3-MeO-SalEen)]PF

Antoine Tissot, Lionel Rechignat, Azzedine Bousseksou, and Marie-Laure Boillot
The elaboration of micro- and nanometric particles of [Fe(3-MeO-SalEen)]PF (H-3-MeO-SalEen being the condensation product of 3-methoxy-substituted salicylaldehyde and N-ethylethylenediamine), a spin-transition compound of molecular nature, is reported. A sudden precipitation approach, using butan-1- ... [J. Mater. Chem. 22, 3411 ] published .

ZnS-nanocrystals/polypyrrole nanocomposite film based immunosensor

Sujeet K. Mishra, Renu Pasricha, Ashok M Biradar, and Rajesh
We report an electrochemically synthesized ZnS nanocrystals modified polypyrrole (PPy) nanocomposite film based immunosensor for the detection of C-reactive protein (alphaCRP). The ZnS-PPy composite film was characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM) and e ... [Appl. Phys. Lett. 100, 053701 ] published .

Temperature and humidity effects on superhydrophobicity of nanocomposite coatings

Yong Han Yeong, Adam Steele, Eric Loth, Ilker Bayer, Guillaume De Combarieu et al.
This work investigates temperature and humidity effects on the superhydrophobicity of polyurethane/organoclay nanocomposites. Previous reports of superhydrophobic degradation at decreasing surface temperatures for both low and high humidity were generally conducted in open environments. However, the ... [Appl. Phys. Lett. 100, 053112 ] published .

Supercapacitive Behaviors of Hierarchically Porous Carbons Prepared by Metal Oxide/Surfactant Templates

Xiaoyan Zhang, Xianyou Wang, Yansong Bai, Xingyan Wang, and Jingcang Su
The hierarchically porous carbons (HPCs) have been prepared by sol-gel self-assembly process with nickel oxide and surfactant as the dual template. The as-prepared HPCs are further activated by HNO. The specific surface area and pore structure of the activated HPCs are characterized by nitrogen adso ... [J. Electrochem. Soc. 159, A431 ] published .

Fluorine-containing block copolymer particles with surface and internal hierarchical microphase separation structures

Shan Qin, Hong Li, Wang Zhang Yuan, and Yongming Zhang
Polymeric particles with diverse surface and internal hierarchical nanostructures were prepared by the dynamic self-assembly of a fluorine-containing diblock copolymer, poly(tert-butylacrylate)-b-poly(2-[(perfluorononenyl) oxy] ethyl methacrylate) (PtBA-b-PFNEMA) in THF/water mixtures. The surface p ... [Soft Matter 8, 2471 ] published .

Self-assembly of alkoxysilanized humic substances into multidomain adlayers at the watersolid interface: linking surface morphology to the molecular structure of the adsorbate

Leonid A. Karpiouk, Sergey A. Ponomarenko, Ahmed Mourran, Dmitry Bochkariov, Aziz M. Muzafarov et al.
Self assembly of natural organic materials (e.g., humic substances) on mineral surfaces leads to the formation of adlayers with physically different domains. However, direct evidence to explain the molecular interactions responsible for the formation of these domains is still missing. Here, we devel ... [Soft Matter 8, 2452 ] published .

Three-dimensional complex-shaped photopolymerized microparticles at liquid crystal interfaces

Angel Martinez, Taewoo Lee, Theodor Asavei, Halina Rubinsztein-Dunlop, and Ivan I. Smalyukh
Microparticles of arbitrary shapes immersed in the bulk of nematic fluids are known to produce dipolar or quadrupolar elastic distortions that can mediate long-range colloidal interactions. We use two-photon photopolymerization to obtain complex-shaped surface-bound microparticles that are then embe ... [Soft Matter 8, 2432 ] published .

Self-assembly of coarse-grained ionic surfactants accelerated by graphics processing units

David N. LeBard, Benjamin G. Levine, Philipp Mertmann, Stephen A. Barr, Arben Jusufi et al.
Due to the relatively long time scales inherent to ionic surfactant self-assembly (>[mu]s), an aggressive computational approach is needed to obtain converged data on micellar solutions. This work presents a study of micellization using a coarse-grained (CG) model of aqueous ionic surfactants in rep ... [Soft Matter 8, 2385 ] published .

Unidirectionally aligned line patterns driven by entropic effects on faceted surfaces

Sung Woo Hong, June Huh, Xiaodan Gu, Dong Hyun Lee, Won Ho Jo et al.
A simple, versatile approach to the directed self-assembly of block copolymers into a macroscopic array of unidirectionally aligned cylindrical microdomains on reconstructed faceted single crystal surfaces or on flexible, inexpensive polymeric replicas was discovered. High fidelity transfer of the ... [Proc. Natl. Acad. Sci. U.S.A. 109, 1402 ] published .

Mirror symmetry breaking and chiral amplification in foldamer-based supramolecular helical aggregates

Simon Azeroual, Jamie Surprenant, Thomas D. Lazzara, Marta Kocun, Ye Tao et al.
Spontaneous asymmetric generation of supramolecular chiral fibers was observed in the folding induced self-assembly of a lock-washer shaped foldamer. A secondary nucleation growth mechanism is proposed to explain the observed chiral amplification or deracemization of these supramolecular fibers. ... [Chem. Commun. 48, 2292 ] published .

Luminescent Au nanocluster superlattices with high thermal stability

Zhijiang Wang, Lina Wu, Wei Cai, and Zhaohua Jiang
The poor thermal stability of nanoparticle superlattices heavily inhibits their practical applications. In present research, using stable thiolate-capped Au(SCHCHCOO)([CH(CH)]N) nanoclusters as the building blocks, novel luminescent Au nanocluster superlattices with high thermal stability have been ... [J. Mater. Chem. 22, 3632 ] published .

Partitioned cooperative self-assembly process: taking the mesopore swelling strategy one step further for the preparation of mesocellular foams

Wei Wang, Weijun Shan, Xinyan Yue, and Hongqiang Ru
This work demonstrates that the combination of recently developed partitioned cooperative self-assembly (PCSA) process with the conventional mesopore swelling strategy can take the preparation of mesocellular foams (MCFs) one step further based on cheap sodium silicate precursor. Compared with conve ... [J. Mater. Chem. 22, 3462 ] published .

Electroless deposition of Cu nanostructures on molecular patterns prepared by dip-pen nanolithography

Yu-Hsu Chang and Chia-Hsin Wang
Cu nanostructures deposited on the top of self-assembled molecular patterns prepared by Dip-pen Nanolithography (DPN) are investigated thoroughly in this study. 16-Mercaptohexadecanoic acid (MHA) molecular patterns are used as templates and CuSO is reduced by electroless deposition method. According ... [J. Mater. Chem. 22, 3377 ] published .

Pillar height dependent formation of unprecedented Pd molecular swing and Pd molecular boat via multicomponent self-assembly

Dipak Samanta, Sankarasekaran Shanmugaraju, Sachin A. Joshi, Yogesh P. Patil, Munirathinam Nethaji et al.
Three-component self-assembly of a cis-blocked 90 degrees Pd(ii) acceptor with a mixture of a tetraimidazole and a linear dipyridyl donor self-discriminated into unusual Pd molecular swing (1) and Pd molecular boat (2), which are characterized by single-crystal X-ray diffraction analysis; their abi ... [Chem. Commun. 48, 2298 ] published .

Interplay between hydrophilic and hydrophobic interactions in the self-assembly of a gemini amphiphilic pseudopeptide: from nano-spheres to hydrogels

Jenifer Rubio, Ignacio Alfonso, M. Isabel Burguete, and Santiago V. Luis
The formation of soluble nano-spheres or stable hydrogels through the self-assembling of a simple gemini amphiphilic pseudopeptide can be controlled by the tuning of the hydrophilic/hydrophobic interactions in aqueous medium. ... [Chem. Commun. 48, 2210 ] published .

Tripeptide self-assembled hydrogels: unexpected twists of chirality

Silvia Marchesan, Christopher D. Easton, Firdawosia Kushkaki, Lynne Waddington, and Patrick G. Hartley
Change of chirality of the first N-terminal amino acid of tripeptides VFF and FFV from l to d results in self-assembled hydrogels at physiological pH from non-assembling l-analogues. Interestingly, changing the chirality of F yields very different nanostructures; nanotapes are observed for VFF, twis ... [Chem. Commun. 48, 2195 ] published .

Fast generation of multiparticle entangled state for flux qubits in a circle array of transmission line resonators with tunable coupling

Z. H. Peng, Yu-xi Liu, Y. Nakamura, and J. S. Tsai
We study a one-step approach to the fast generation of Greenberger-Horne-Zeilinger (GHZ) states in a circuit QED system with superconducting flux qubits. The GHZ state can be generated in about 10 ns, which is much shorter than the coherence time of flux qubits and comparable with the time of single ... [Phys. Rev. B 85, 024537 ] published .

Characterization of a Two-Transmon Processor with Individual Single-Shot Qubit Readout

A. Dewes, F. R. Ong, V. Schmitt, R. Lauro, N. Boulant et al.
We report the characterization of a two-qubit processor implemented with two capacitively coupled tunable superconducting qubits of the transmon type, each qubit having its own nondestructive single-shot readout. The fixed capacitive coupling yields the sqrt(iSWAP) two-qubit gate for a suitable inte ... [Phys. Rev. Lett. 108, 057002 ] published .

Local Unitary Classification of Arbitrary Dimensional Multipartite Pure States

Bin Liu, Jun-Li Li, Xikun Li, and Cong-Feng Qiao
We propose a practical entanglement classification scheme for general multipartite pure states in arbitrary dimensions under local unitary equivalence by exploiting the high order singular value decomposition technique and local symmetries of the states. By virtue of this scheme, the method of deter ... [Phys. Rev. Lett. 108, 050501 ] published .

Indistinguishable Entangled Photons Generated by a Light-Emitting Diode

R. M. Stevenson, C. L. Salter, J. Nilsson, A. J. Bennett, M. B. Ward et al.
A linear optical quantum computer relies on interference between photonic qubits for logic, and entanglement for near-deterministic operation. Here we measure the interference and entanglement properties of photons emitted by a quantum dot embedded within a light-emitting diode. We show that pairs o ... [Phys. Rev. Lett. 108, 040503 ] published .

Entanglement spectra of coupled S=(1/2) spin chains in a ladder geometry

Andreas M. Lauchli and John Schliemann
We study the entanglement spectrum of spin-1/2 XXZ ladders both analytically and numerically. Our analytical approach is based on perturbation theory starting either from the limit of strong rung coupling, or from the opposite case of dominant coupling along the legs. In the former case we find to l ... [Phys. Rev. B 85, 054403 ] published .

Chiral-mediated entanglement in an Aharonov-Bohm ring

Bruno Rizzo, Liliana Arrachea, and Juan Pablo Paz
We study the orbital entanglement in a biased Aharonov-Bohm ring connected in a four-terminal setup. We find that the concurrence achieves a maximum when the magnetic flux Phi coincides with an integer number of a half flux quantum Phi/2. We show that this behavior is a consequence of the existence ... [Phys. Rev. B 85, 045442 ] published .

Matrix product state based algorithm for determining dispersion relations of quantum spin chains with periodic boundary conditions

B. Pirvu, J. Haegeman, and F. Verstraete
We study a matrix product state algorithm to approximate excited states of translationally invariant quantum spin systems with periodic boundary conditions. By means of a momentum eigenstate ansatz generalizing the one of Ostlund and Rommer [see S. Ostlund and S. Rommer, Phys. Rev. Lett. 75, 3537 (1 ... [Phys. Rev. B 85, 035130 ] published .

Storage and retrieval of a microwave field in a spin ensemble

Y. Kubo, I. Diniz, A. Dewes, V. Jacques, A. Dreau et al.
We report the storage and retrieval of a small microwave field from a superconducting resonator into collective excitations of a spin ensemble. The spins are nitrogen-vacancy centers in a diamond crystal. The storage time of the order of 30 ns is limited by inhomogeneous broadening of the spin ensem ... [Phys. Rev. A 85, 012333 ] published .

Spin dynamics in the frozen state of the dipolar spin ice material DyTiO

L. R. Yaraskavitch, H. M. Revell, S. Meng, K. A. Ross, H. M. L. Noad et al.
Low-temperature magnetic ac susceptibility measurements of single-crystal dipolar spin ice DyTiO are presented. The relaxation is found to exhibit thermally activated Arrhenius behavior with an activation energy of 9.79 K (~9J), which is not consistent with a simple scaling of 6J, as previously foun ... [Phys. Rev. B 85, 020410 ] published .

Method for measuring the entanglement of formation for arbitrary-dimensional pure states

Ming Li and Shao-Ming Fei
Entanglement of formation is an important measure of quantum entanglement. We present an experimental way to measure the entanglement of formation for arbitrary dimensional pure states. The measurement only evolves local quantum mechanical observables. ... [Phys. Rev. A 85, 014304 ] published .

Photon-assisted conditionality for double-dot charge qubits in a single-mode cavity

Alexander V. Tsukanov
The problems of the design, control, and interaction of the single-electron double-dot charge qubits coherently coupled to the optical cavity mode are studied theoretically. A way to overcome the challenges concerned with the use of classical laser pulses for a qubit state engineering is described, ... [Phys. Rev. A 85, 012331 ] published .

Quantum privacy witness

Konrad Banaszek, Karol Horodecki, and Pawel Horodecki
While it is usually known that the mean value of a single observable is enough to detect entanglement or its distillability, the counterpart of such an approach in the case of quantum privacy has been missing. Here we develop the concept of a privacy witness, i.e., a single observable that may detec ... [Phys. Rev. A 85, 012330 ] published .

Trapping a particle of a quantum walk on the line

Antoni Wojcik, Tomasz Luczak, Pawel Kurzynski, Andrzej Grudka, Tomasz Gdala et al.
We observe that changing a phase at a single point in a discrete quantum walk results in a rather surprising localization effect. For certain values of this phase change the possibility of localization strongly depends on the internal coin state of the walker. ... [Phys. Rev. A 85, 012329 ] published .

Creating quantum correlations through local nonunitary memoryless channels

Francesco Ciccarello and Vittorio Giovannetti
We show that two qubits, initially in a fully classical state, can develop significant quantum correlations as measured by the quantum discord (QD) under the action of a local memoryless noise (specifically we consider the case of a Markovian amplitude-damping channel). This is analytically proven a ... [Phys. Rev. A 85, 010102 ] published .

Short circuit current improvement in planar heterojunction organic solar cells by multijunction charge transfer

J. C. Wang, S. Q. Shi, C. W. Leung, S. P. Lau, K. Y. Wong et al.
A multijunction structure was applied on an organic photovoltaic (OPV) device for broadening the absorption spectrum and enhancing the power conversion efficiency through charge transfer process. By inserting the tris[4-(2-thienyl)]amine (TTPA) into a boron subphthalocyanine chloride (SubPc)/C OPV d ... [Appl. Phys. Lett. 100, 053301 ] published .

Spin-inversion in nanoscale graphene sheets with a Rashba spin-orbit barrier

Somaieh Ahmadi, Mahdi Esmaeilzadeh, Esmaeil Namvar, and Genhua Pan
Spin-inversion properties of an electron in nanoscale graphene sheets with a Rashba spin-orbit barrier is studied using transfer matrix method. It is found that for proper values of Rashba spin-orbit strength, perfect spin-inversion can occur in a wide range of electron incident angle near the norma ... [AIP Advances 2, 012130 ] published .

Mapping the electronic properties of individual graphene grain boundaries

Levente Tapaszto, Peter Nemes-Incze, Gergely Dobrik, Kwon Jae Yoo, Chanyong Hwang et al.
Grain boundaries, the characteristic topological defects of chemical vapor deposition grown graphene samples, are expected to substantially alter the electronic properties of the unperturbed graphene lattice. However, there is very little experimental insight into the underlying mechanisms. Here, we ... [Appl. Phys. Lett. 100, 053114 ] published .

Structural phase transition of graphene caused by GaN epitaxy

Y. Gohda and S. Tsuneyuki
We report first-principles predictions, where the structure of graphene changes drastically with the epitaxial growth of GaN (which has been performed experimentally). We identify GaN-sqrt(3) x sqrt(3)/graphene-2 x 2 superstructure as the most probable interface atomic structure, where three C-C b ... [Appl. Phys. Lett. 100, 053111 ] published .

Fabrication and magnetic properties of free-standing Ni nanotube arrays with controllable wall thickness

Y. L. Li, S. L. Tang, R. Xie, Y. Wang, M. Yang et al.
Free-standing Ni nanotubes were fabricated on silicon substrate using anodic aluminum oxide/polypyrrole composite template. The diameter, length, and wall thickness of the nanotubes can be precisely and independently controlled. Magnetic measurements show that the magnetic anisotropic properties are ... [Appl. Phys. Lett. 100, 052402 ] published .

Electrically Tunable Quantum Anomalous Hall Effect in Graphene Decorated by 5d Transition-Metal Adatoms

Hongbin Zhang, Cesar Lazo, Stefan Blugel, Stefan Heinze, and Yuriy Mokrousov
Based on first-principles calculations, we predict that 5d transition metals on graphene present a unique class of hybrid systems exhibiting topological transport effects that can be manipulated effectively by external electric fields. The origin of this phenomenon lies in the exceptional magnetic p ... [Phys. Rev. Lett. 108, 056802 ] published .

Time-Resolved Two-Photon Photoemission of Unoccupied Electronic States of Periodically Rippled Graphene on Ru(0001)

N. Armbrust, J. Gudde, P. Jakob, and U. Hofer
The unoccupied electronic states of epitaxially grown graphene on Ru(0001) have been explored by time- and angle-resolved two-photon photoemission. We identify a Ru derived resonance and a Ru/graphene interface state at 0.91 and 2.58 eV above the Fermi level, as well as three image-potential derived ... [Phys. Rev. Lett. 108, 056801 ] published .

Direct Observation of Sub-100 fs Mobile Charge Generation in a Polymer-Fullerene Film

D. G. Cooke, F. C. Krebs, and P. U. Jepsen
The formation of mobile charges in a roll-to-roll processed poly-3-hexylthiophenefullerene bulk heterojunction film is observed directly by using transient terahertz spectroscopy with sub-100 fs temporal resolution. The transient terahertz ac conductivity reveals that 20% of the incident pump photon ... [Phys. Rev. Lett. 108, 056603 ] published .

Complete Optical Absorption in Periodically Patterned Graphene

Sukosin Thongrattanasiri, Frank H. L. Koppens, and F. Javier Garcia de Abajo
We demonstrate that 100% light absorption can take place in a single patterned sheet of doped graphene. General analysis shows that a planar array of small particles with losses exhibits full absorption under critical-coupling conditions provided the cross section of each individual particle is comp ... [Phys. Rev. Lett. 108, 047401 ] published .

Role of intermolecular charge delocalization on electron transport in fullerene aggregates

Hiroyuki Tamura and Masaru Tsukada
Electron transfer in fullerene aggregates plays a key role in organic solar cells and organic transistors. Electron transfer overcoming a potential barrier is proposed to occur during the charge separation in organic solar cells. We analyze the electron transfers in C aggregates using quantum dynami ... [Phys. Rev. B 85, 054301 ] published .

Single-wall carbon nanotubes as coherent plasmon generators

I. V. Bondarev
The possibility of low-energy surface plasmon amplification by optically excited excitons in small-diameter single-wall carbon nanotubes is theoretically demonstrated. The nonradiative exciton-plasmon energy transfer causes the buildup of macroscopic population numbers of coherent localized surface ... [Phys. Rev. B 85, 035448 ] published .

Electronic properties and STM images of doped bilayer graphene

Stephane-Olivier Guillaume, Bing Zheng, Jean-Christophe Charlier, and Luc Henrard
Electronic structures and scanning tunneling microscopy (STM) patterns of boron- and nitrogen-doped bilayer graphene are predicted using state-of-the-art first-principles calculations. Asymmetric doping is considered, leading to different charge-carrier densities on each graphene layer and to a band ... [Phys. Rev. B 85, 035444 ] published .

Graphene on SiC as a Q-switcher for a 2 [mu]m laser

Qing Wang, Hao Teng, Yuwan Zou, Zhiguo Zhang, Dehua Li et al.
Double-layer graphene epitaxially grown on silicon carbide was used to Q-switch a Tm:YAG laser. Stable Q-switched laser pulses at the central wavelength of 2.01 [mu]m were obtained. The maximum average output power, pulse repetition rate, and single pulse energy were 38 mW, 27.9 kHz, and 1.74 [mu]J, ... [Opt. Lett. 37, 395 ] published .

Dirac cones reshaped by interaction effects in suspended graphene

D. C. Elias, R. V. Gorbachev, A. S. Mayorov, S. V. Morozov, A. A. Zhukov et al.
Abstract not available. [Nature Phys. 8, 172 ] published .

Chiral superconductivity from repulsive interactions in doped graphene

Rahul Nandkishore, L. S. Levitov, and A. V. Chubukov
Chiral superconductivity, which breaks time-reversal symmetry, can exhibit a wealth of fascinating properties that are highly sought after for nanoscience applications. We identify doped graphene monolayer as a system where chiral superconductivity can be realized. In this material, a unique situati ... [Nature Phys. 8, 158 ] published .

Phonon-mediated superconductivity in graphene by lithium deposition

Gianni Profeta, Matteo Calandra, and Francesco Mauri
Graphene is the physical realization of many fundamental concepts and phenomena in solid-state physics. However, in the list of graphenes many remarkable properties, superconductivity is notably absent. If it were possible to find a way to induce superconductivity, it could improve the performance ... [Nature Phys. 8, 131 ] published .

Extremely efficient flexible organic light-emitting diodes with modified graphene anode

Tae-Hee Han, Youngbin Lee, Mi-Ri Choi, Seong-Hoon Woo, Sang-Hoon Bae et al.
Although graphene films have a strong potential to replace indium tin oxide anodes in organic light-emitting diodes (OLEDs), to date, the luminous efficiency of OLEDs with graphene anodes has been limited by a lack of efficient methods to improve the low work function and reduce the sheet resistance ... [Nat. Photonics 6, 105 ] published .

Angular distribution of field emitted electrons from vertically aligned carbon nanotube arrays

S. Iacobucci, M. Fratini, A. Rizzo, F. Scarinci, Y. Zhang et al.
Angular field emission (FE) properties of vertically aligned carbon nanotube arrays have been measured on samples grown by plasma enhanced chemical vapor deposition and characterized by scanning electron microscope and I-V measurements. These properties determine the angular divergence of electron b ... [Appl. Phys. Lett. 100, 053116 ] published .

Plasma enables edge-to-center-oriented graphene nanoarrays on Si nanograss

S. Kumar, I. Levchenko, Q. J. Cheng, J. Shieh, and K. Ostrikov
The formation of clearly separated vertical graphene nanosheets on silicon nanograss support is demonstrated. The plasma-enabled, two-stage mask-free process produced self-organized vertical graphenes of a few carbon layers (as confirmed by advanced microanalysis), prominently oriented in the substr ... [Appl. Phys. Lett. 100, 053115 ] published .

Negative differential spin conductance in doped zigzag graphene nanoribbons

Ting-Ting Wu, Xue-Feng Wang, Ming-Xing Zhai, Hua Liu, Liping Zhou et al.
The spin dependent charge transport in zigzag graphene nanoribbons (ZGNRs) has been investigated by the nonequilibrium Green's function method combined with the density functional theory at the local spin density approximation. The current versus voltage curve shows distinguished behaviors for symme ... [Appl. Phys. Lett. 100, 052112 ] published .

Electronic transport anisotropy of buckling graphene under uniaxial compressive strain: Ab initio study

Yang Xu, Haiyuan Gao, Huabin Chen, You Yuan, Kaicheng Zhu et al.
Electronic transport properties of graphene under uniaxial compressive strain are studied using ab initio calculations. With approximate thermal perturbation, buckling occurs when strain exceeds a threshold, comparing to flat unperturbed structures. Transmissions of flat graphene compressed along zi ... [Appl. Phys. Lett. 100, 052111 ] published .

Effect of electric field on the band structure of graphene/boron nitride and boron nitride/boron nitride bilayers

Radhakrishnan Balu, Xiaoliang Zhong, Ravindra Pandey, and Shashi P. Karna
Effect of electric field on the band structures of graphene/boron nitride (BN) and BN/BN bilayers is investigated within the framework of density functional theory. The calculated bandgap of the graphene/BN bilayer increases, although by small amount, with applied electric field. In the case of BN/B ... [Appl. Phys. Lett. 100, 052104 ] published .

Quantum Hall effect in bottom-gated epitaxial graphene grown on the C-face of SiC

B. Jouault, N. Camara, B. Jabakhanji, A. Caboni, C. Consejo et al.
We demonstrate that the carrier concentration of epitaxial graphene devices grown on the C-face of a SiC substrate is efficiently modulated by a buried gate. The gate is fabricated via the implantation of nitrogen atoms in the SiC crystal. The charge neutrality point is observed close to gate voltag ... [Appl. Phys. Lett. 100, 052102 ] published .

Beam-scanning planar lens based on graphene

Hong Ju Xu, Wei Bing Lu, Yun Jiang, and Zheng Gao Dong
One of the most important advantages of graphene is the capability of dynamically tuning its conductivity by means of chemical doping or gate voltage. Based on this property, we propose a planar gradient index graphene-based lens transforming spherical waves of the transverse-magnetic (TM) surface p ... [Appl. Phys. Lett. 100, 051903 ] published .

Effect of uni-axial strain on THz/far-infrared response of graphene

JooYoun Kim, Chul Lee, Sukang Bae, Sang Jin Kim, Keun Soo Kim et al.
We present polarized optical transmission study of uniaxially strained large scale graphene in THz/far-infrared (IR) frequency region. Graphene was supported on stretchable polyethylene substrate and they were elongated up to 20% (DeltaL/L = 0.2) by applying tensile force. For the IR light polarized ... [Appl. Phys. Lett. 100, 041910 ] published .

Electrical transport across metal/two-dimensional carbon junctions: Edge versus side contacts

Yihong Wu, Ying Wang, Jiayi Wang, Miao Zhou, Aihua Zhang et al.
Metal/two-dimensional carbon junctions are characterized by using a nanoprobe in an ultrahigh vacuum environment. Significant differences were found in bias voltage (V) dependence of differential conductance (dI/dV) between edge- and side-contact; the former exhibits a clear linear relationship (i.e ... [AIP Advances 2, 012132 ] published .

Realization of a micrometre-sized stochastic heatengine

Valentin Blickle and Clemens Bechinger
The conversion of energy into mechanical work is essential for almost any industrial process. The original description of classical heat engines by Sadi Carnot in 1824 has largely shaped our understanding of work and heat exchange during macroscopic thermodynamic processes. Equipped with our presen ... [Nature Phys. 8, 143 ] published .

DNA Transport and Delivery in Thermal Gradients near Optofluidic Resonators

Xavier Serey, Sudeep Mandal, Yih-Fan Chen, and David Erickson
Heat generation and its impact on DNA transport in the vicinity of an optofluidic silicon photonic crystal resonator are studied theoretically and experimentally. The temperature rise is measured to be as high as 57 K for 10 mW of input power. The resulting optical trapping and biomolecular sensing ... [Phys. Rev. Lett. 108, 048102 ] published .

Pulsed contact resonance for atomic force microscopy nanomechanical measurements

Jason P. Killgore and Donna C. Hurley
We demonstrate an improved technique for nanomechanical imaging in atomic force microscopy. By merging the sensitivity to contact stiffness inherent to contact resonance (CR) spectroscopy with the delicate nature and potential for adhesion data of pulsed-force mode, we address major shortcomings of ... [Appl. Phys. Lett. 100, 053104 ] published .

Mode shape and dispersion relation of bending waves in thin silicon membranes

Reimar Waitz, Stephan Nossner, Michael Hertkorn, Olivier Schecker, and Elke Scheer
We study the vibrational behavior of silicon membranes with a thickness of a few hundred nanometers and macroscopic lateral size. A piezo is used to couple in transverse vibrations, which we monitor with a phase-shift interferometer using stroboscopic light. The observed wave pattern of the membrane ... [Phys. Rev. B 85, 035324 ] published .

Optical cavity cooling of mechanical modes of a semiconductor nanomembrane

K. Usami, A. Naesby, T. Bagci, B. Melholt Nielsen, J. Liu et al.
Mechanical oscillators can be optically cooled using a technique known as optical-cavity back-action. Cooling of composite metalsemiconductor mirrors, dielectric mirrors and dielectric membranes has been demonstrated. Here we report cavity cooling of mechanical modes in a high-quality-factor and opt ... [Nature Phys. 8, 168 ] published .

High-frequency electrical charge and spin control in a single InGaAs quantum dot

J. Nannen, W. Quitsch, S. Eliasson, T. Kummell, and G. Bacher
We report on the charging behavior of a single self-assembled InGaAs quantum dot with unpolarized and spin-polarized electrons under direct current (DC) and high-frequency biasing. The tunnel coupling of the quantum dot to a spin-polarized electron reservoir leads to characteristic voltage dependenc ... [Phys. Rev. B 85, 035325 ] published .

Boosting optical nonlinearities in epsilon-near-zero plasmonic channels

Christos Argyropoulos, Pai-Yen Chen, Giuseppe D'Aguanno, Nader Engheta, and Andrea Alu
The anomalous transmission properties of zero-permittivity ultranarrow channels are used to boost Kerr nonlinearities and achieve switching and bistable response for moderate optical intensities. Strong field enhancement, uniform all along the channel, is a typical feature of epsilon-near-zero super ... [Phys. Rev. B 85, 045129 ] published .

Plasmonic crystals for ultrafast nanophotonics: Optical switching of surface plasmon polaritons

M. Pohl, V. I. Belotelov, I. A. Akimov, S. Kasture, A. S. Vengurlekar et al.
We demonstrate that the dispersion of surface plasmon polaritons in a periodically perforated gold film can be efficiently manipulated by femtosecond laser pulses in spectral regions far from the intrinsic gold resonances. Using a time- and frequency-resolved pump-probe technique we observe shifting ... [Phys. Rev. B 85, 081401 ] published .

Greatly enhanced continuous-wave terahertz emission by nano-electrodes in a photoconductive photomixer

H. Tanoto, J. H. Teng, Q. Y. Wu, M. Sun, Z. N. Chen et al.
An efficient, room-temperature-operation continuous-wave terahertz source will greatly benefit compact terahertz system development for high-resolution terahertz spectroscopy and imaging applications. Here, we report highly efficient continuous-wave terahertz emission using nanogap electrodes in a p ... [Nat. Photonics 6, 121 ] published .

Bloch-Wave Engineering of Quantum Dot Micropillars for Cavity Quantum Electrodynamics Experiments

M. Lermer, N. Gregersen, F. Dunzer, S. Reitzenstein, S. Hofling et al.
We have employed Bloch-wave engineering to realize submicron diameter high quality factor GaAs/AlAs micropillars (MPs). The design features a tapered cavity in which the fundamental Bloch mode is subject to an adiabatic transition to match the Bragg mirror Bloch mode. The resulting reduced scatterin ... [Phys. Rev. Lett. 108, 057402 ] published .

Optically Gated Resonant Emission of Single Quantum Dots

H. S. Nguyen, G. Sallen, C. Voisin, Ph. Roussignol, C. Diederichs et al.
We report on the resonant emission in coherently driven single semiconductor quantum dots. We demonstrate that an ultraweak nonresonant laser acts as an optical gate for the quantum dot resonant response. We show that the gate laser suppresses Coulomb blockade at the origin of a resonant emission qu ... [Phys. Rev. Lett. 108, 057401 ] published .

Coaxial multishell nanowires with high-quality electronic interfaces and tunable optical cavities for ultrathin photovoltaics

Thomas J. Kempa, James F. Cahoon, Sun-Kyung Kim, Robert W. Day, David C. Bell et al.
Silicon nanowires (NWs) could enable low-cost and efficient photovoltaics, though their performance has been limited by nonideal electrical characteristics and an inability to tune absorption properties. We overcome these limitations through controlled synthesis of a series of polymorphic core/mult ... [Proc. Natl. Acad. Sci. U.S.A. 109, 1407 ] published .

Strongly correlated photons on a chip

Andreas Reinhard, Thomas Volz, Martin Winger, Antonio Badolato, Kevin J. Hennessy et al.
Optical nonlinearities at the single-photon level are key ingredients for future photonic quantum technologies. Prime candidates for the realization of the strong photonphoton interactions necessary for implementing quantum information processing tasks, as well as for studying strongly correlated ph ... [Nat. Photonics 6, 93 ] published .

Self-driving capacitive cantilevers for high-frequency atomic force microscopy

Keith A. Brown, Benjamin H. Yang, and R. M. Westervelt
We demonstrate a simple way to actuate an atomic force microscope cantilever at high frequencies by electrically driving a thin-film capacitor on its surface. Capacitive driving directly actuates the vibrational mode of the cantilever, removing the effects of unwanted mechanical modes present in con ... [Appl. Phys. Lett. 100, 053110 ] published .

Tapping-mode force spectroscopy using cantilevers with interferometric high-bandwidth force sensors

A. Fatih Sarioglu, Sergei Magonov, and Olav Solgaard
We quantitatively map the surface forces and elastic modulus in tapping-mode atomic force microscopy (AFM). To achieve this, we use custom-built cantilevers with interferometric high-bandwidth force sensors that can resolve nonlinear tip-sample interaction forces, combined with a set of algorithms t ... [Appl. Phys. Lett. 100, 053109 ] published .

Optically Engineering the Topological Properties of a Spin Hall Insulator

Balazs Dora, Jerome Cayssol, Ferenc Simon, and Roderich Moessner
Time-periodic perturbations can be used to engineer topological properties of matter by altering the Floquet band structure. This is demonstrated for the helical edge state of a spin Hall insulator in the presence of monochromatic circularly polarized light. The inherent spin structure of the edge s ... [Phys. Rev. Lett. 108, 056602 ] published .

Spin Coupling and Orbital Angular Momentum Quenching in Free Iron Clusters

M. Niemeyer, K. Hirsch, V. Zamudio-Bayer, A. Langenberg, M. Vogel et al.
Magnetic spin and orbital moments of size-selected free iron cluster ions Fe (n=320) have been determined via x-ray magnetic circular dichroism spectroscopy. Iron atoms within the clusters exhibit ferromagnetic coupling except for Fe, where the central atom is coupled antiferromagnetically to the at ... [Phys. Rev. Lett. 108, 057201 ] published .

Atomistic Spin Dynamic Method with both Damping and Moment of Inertia Effects Included from First Principles

Satadeep Bhattacharjee, Lars Nordstrom, and Jonas Fransson
We consider spin dynamics for implementation in an atomistic framework and we address the feasibility of capturing processes in the femtosecond regime by inclusion of moment of inertia. In the spirit of an s-d-like interaction between the magnetization and electron spin, we derive a generalized equa ... [Phys. Rev. Lett. 108, 057204 ] published .

Quantum anomalous Hall effect with tunable Chern number in magnetic topological insulator film

Hua Jiang, Zhenhua Qiao, Haiwen Liu, and Qian Niu
We study the possibility of realizing quantum anomalous Hall (QAH) effect with tunable Chern number through doping magnetic elements in a multilayer topological insulator film. We find that high Chern number QAH phases exist in ideal neutral samples and can make transition to another QAH phase direc ... [Phys. Rev. B 85, 045445 ] published .

Thermal equilibration and thermally induced spin currents in a thin-film ferromagnet on a substrate

Matthew R. Sears and Wayne M. Saslow
Recent spin-Seebeck experiments on thin ferromagnetic films apply a temperature difference DeltaT along the length x and measure a (transverse) voltage difference DeltaV along the width y. The connection between these involves: (1) thermal equilibration between sample and substrate, (2) spin current ... [Phys. Rev. B 85, 035446 ] published .

Spin transport in poly(metalarenylsilane)

Yukihito Matsuura
We focused on the spin transport properties of polymers containing ferrocene and the related transition-metal-benzene sandwich compound (metal = Cr and V) with a silicon bridge such as poly(ferrocenylsilane) and poly(metalarenylsilane). As a model system, a sulfur-substituted oligomer was put on gol ... [Appl. Phys. Lett. 100, 053303 ] published .

All-metallic lateral spin valves using CoFe(GeGa) Heusler alloy with a large spin signal

Y. K. Takahashi, S. Kasai, S. Hirayama, S. Mitani, and K. Hono
A large spin signal (DeltaR) of 12.8 mOmega at room temperature is demonstrated in an all-metallic lateral spin valve (LSV) device comprising of ferromagnetic wire of a highly spin-polarized CoFe(GeGa) Heusler alloy and a Cu wire. From the results on multi-terminal LSV devices, the origin of the lar ... [Appl. Phys. Lett. 100, 052405 ] published .

Doppler velocimetry of spin propagation in a two-dimensional electron gas

Luyi Yang, J. D. Koralek, J. Orenstein, D. R. Tibbetts, J. L. Reno et al.
Controlling the flow of electrons by manipulating their spin is a key to the development of spin-based electronics. Recent demonstrations of electrical-gate control in spin-transistor configurations have shown great promise, but operation at room temperature remains elusive. Further progress require ... [Nature Phys. 8, 153 ] published .

Quantitative modeling of spin relaxation in quantum dots

J. P. Hansen, S. A. Sorngard, M. Forre, and E. Rasanen
We use numerically exact diagonalization to calculate the spin-orbit- and phonon-induced triplet-singlet relaxation rate in a two-electron quantum dot exposed to a tilted magnetic field. Our scheme includes a three-dimensional description of the quantum dot, the Rashba and the linear and cubic Dress ... [Phys. Rev. B 85, 035326 ] published .

Spectral properties of Luttinger liquids: A comparative analysis of regular, helical, and spiral Luttinger liquids

Bernd Braunecker, Cristina Bena, and Pascal Simon
We provide analytic expressions for the Green's functions in position-frequency space as well as for the tunneling density of states of various Luttinger liquids at zero temperature: the standard spinless and spinful Luttinger liquids, the helical Luttinger liquid at the edge of a topological insula ... [Phys. Rev. B 85, 035136 ] published .

Convergence of Energy Scales on the Approach to a Local Quantum Critical Point

Y. Nishikawa, D. J. G. Crow, and A. C. Hewson
We find the emergence of strong correlations and universality on the approach to the quantum critical points of a two-impurity Anderson model. The two impurities are coupled by an interimpurity exchange interaction J and direct interaction U and are hybridized with separate conduction channels. The ... [Phys. Rev. Lett. 108, 056402 ] published .

X-Ray Diagnosis of the Pressure Induced Mott Nonmetal-Metal Transition

A. Levy, F. Dorchies, A. Benuzzi-Mounaix, A. Ravasio, F. Festa et al.
The evolution of the K-edge x-ray absorption near-edge spectroscopy (XANES) spectrum is investigated for an aluminum plasma expanding from the solid density down to 0.5 g/cm, with temperatures lying from 5 down to 2 eV. The dense plasma is generated by nanosecond laser-induced shock compression. Th ... [Phys. Rev. Lett. 108, 055002 ] published .

Resonance-hybrid states in a triple quantum dot

S. Amaha, T. Hatano, H. Tamura, S. Teraoka, T. Kubo et al.
Delocalization by resonance between contributing structures explains the enhanced stability of resonance-hybrid molecules. Here we report the realization of resonance-hybrid states in a few-electron triple quantum dot (TQD) obseved by excitation spectroscopy. The stabilization of the resonance-hybri ... [Phys. Rev. B 85, 081301 ] published .

Time scales in the dynamics of an interacting quantum dot

L. Debora Contreras-Pulido, Janine Splettstoesser, Michele Governale, Jurgen Konig, and Markus Buttiker
We analyze the dynamics of a single-level quantum dot with Coulomb interaction, weakly tunnel coupled to an electronic reservoir, after it has been brought out of equilibrium, e.g., by a step-pulse potential. We investigate the exponential decay toward the equilibrium state, which is governed by thr ... [Phys. Rev. B 85, 075301 ] published .

Room-temperature single molecular memory

Shinya Kano, Yasuyuki Yamada, Kentaro Tanaka, and Yutaka Majima
Single molecular memory operation was observed on a porphyrin derivative by scanning tunneling microscopy at room temperature. A porphyrin derivative with four disulfide groups was chemically synthesized and chemisorbed on a Au(111) surface. Coulomb blockade behaviors and switching behaviors in curr ... [Appl. Phys. Lett. 100, 053101 ] published .

Position-controlled [100] InP nanowire arrays

Jia Wang, Sebastien Plissard, Moira Hocevar, Thuy T. T. Vu, Tilman Zehender et al.
We investigate the growth of vertically standing [100] zincblende InP nanowire (NW) arrays on InP (100) substrates in the vapor-liquid-solid growth mode using low-pressure metal-organic vapor-phase epitaxy. Precise positioning of these NWs is demonstrated by electron beam lithography. The vertical N ... [Appl. Phys. Lett. 100, 053107 ] published .

High-temperature annealing of thin Au films on Si: Growth of SiO nanowires or Au dendritic nanostructures?

F. Ruffino, L. Romano, G. Pitruzzello, and M. G. Grimaldi
A simple and low-cost approach for the large-scale production of Au nanodendritic structures on Si is presented. Starting from the methodology involving deposition of a Au film on Si and heating the system to high temperatures in an inert ambient containing trace amounts of oxygen for the growth of ... [Appl. Phys. Lett. 100, 053102 ] published .

Formation of Ge Nanoripples on Vicinal Si (1110): From Stranski-Krastanow Seeds to a Perfectly Faceted Wetting Layer

G. Chen, B. Sanduijav, D. Matei, G. Springholz, D. Scopece et al.
Ge growth on high-indexed Si (1110) is shown to result in the spontaneous formation of a perfectly {105} faceted one-dimensional nanoripple structure. This evolution differs from the usual Stranski-Krastanow growth mode because from initial ripple seeds a faceted Ge layer is formed that extends down ... [Phys. Rev. Lett. 108, 055503 ] published .

Surface Nanocrystallization of an Ionic Liquid

Yoonnam Jeon, David Vaknin, Wei Bu, Jaeho Sung, Yukio Ouchi et al.
Surface crystallization at the vapor-liquid interface of the ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) is observed in synchrotron x-ray diffraction studies. Sharp Bragg reflections emerge in grazing-angle x-ray diffraction patterns 37 degrees C above the bulk melting temperatur ... [Phys. Rev. Lett. 108, 055502 ] published .

Mechanism of stress relaxation in nanocrystalline Fe-N thin films

Ranjeeta Gupta, Ajay Gupta, W. Leitenberger, and R. Ruffer
The mechanism of stress relaxation in nanocrystalline Fe-N thin film has been studied. The as-deposited film possesses a strong in-plane compressive stress which relaxes with thermal annealing. Precise diffusion measurements using nuclear resonance reflectivity show that stress relaxation does not i ... [Phys. Rev. B 85, 075401 ] published .

Size effects on elasticity, yielding, and fracture of silver nanowires: In situ experiments

Yong Zhu, Qingquan Qin, Feng Xu, Fengru Fan, Yong Ding et al.
This paper reports the quantitative measurement of a full spectrum of mechanical properties of fivefold twinned silver (Ag) nanowires (NWs), including Young's modulus, yield strength, and ultimate tensile strength. In-situ tensile testing of Ag NWs with diameters between 34 and 130 nm was carried ou ... [Phys. Rev. B 85, 045443 ] published .

Quantitative x-ray phase nanotomography

Ana Diaz, Pavel Trtik, Manuel Guizar-Sicairos, Andreas Menzel, Pierre Thibault et al.
X-ray ptychographic computed tomography has recently emerged as a nondestructive characterization tool for samples with representative sizes of several tens of micrometers, yet offering a resolution currently lying in but not limited to the 100-nm range. Here we evaluate the quantitativeness of this ... [Phys. Rev. B 85, 020104 ] published .

A nano-cheese-cutter to directly measure interfacial adhesion of freestanding nano-fibers

Xin Wang, Johnny F. Najem, Shing-Chung Wong, and Kai-tak Wan
A nano-cheese-cutter is fabricated to directly measure the adhesion between two freestanding nano-fibers. A single electrospun fiber is attached to the free end of an atomic force microscope cantilever, while a similar fiber is similarly prepared on a mica substrate in an orthogonal direction. Exter ... [J. Appl. Phys. 111, 024315 ] published .