Journal of Applied Physics is an influential international journal publishing significant new experimental and theoretical results of applied physics research. Topics covered in Journal of Applied Physics are diverse, reflecting the most current applied physics research, and include areas of particular emerging interest. Content is published online daily and collected into weekly online and printed issues (48 issues per year).
Editor's Picks

The processing parameters which favour the onset of an impurity band conduction around room temperature with a contemporaneous elevated ptype conductivity in Al ^{+} implanted 4HSiC are highlighted by comparing original and literature results. In the examined cases, Al is implanted at 300–400 °C, in concentrations from below to above the Al solubility limit in 4HSiC (2 × 10^{20 }cm^{−3}) and post implantation annealing temperature is ≥1950 °C. Transport measurements feature the onset of an impurity band conduction, appearing at increasing temperature for increasing Al implant dose, until this transport mechanism is enabled around room temperature. This condition appears suitable to guarantee a thermal stability of the electrical properties. In this study, the heaviest doped and less resistive samples (Al implanted concentration of 5 × 10^{20 }cm^{−3} and resistivity of about 2 × 10^{−2} Ω cm) show a carrier density above the Al solubility limit, which is consistent with at least a 50% electrical activation for a 15% compensation. The model of Miller and Abrahams well describes the resistivity data of the lower doped sample, whereas a deviation from the behaviour predicted by such a model is observed in the higher doped specimens, consistent with the occurrence of a variable range hopping at low temperature.

We discuss the necessity of the exact implicit Momentum Relaxation Time (MRT) solution of the Boltzmann transport equation in order to achieve reliable carrier mobility results in semiconductor nanowires. Firstly, the implicit solution for a 1D electron gas with a isotropic bandstructure is presented resulting in the formulation of a simple matrix system. Using this solution as a reference, the explicit approach is demonstrated to be inaccurate for the calculation of inelastic anisotropic mechanisms such as polar optical phonons, characteristic of IIIV materials. Its validity for elastic and isotropic mechanisms is also evaluated. Finally, the implications of the MRT explicit approach inaccuracies on the total mobility of Si and IIIV NWs are studied.

With recent advances in atom probe tomography of insulators and semiconductors, there is a need to understand high electrostatic field effects in these materials as well as the details of field evaporation. We use density functional theory to study field effects in ZnO clusters calculating the potential energy curves, the local field distribution, the polarizability, and the dielectric constant as a function of field strength. We confirm that, as in MgO, the HOMOLUMO gap of a ZnO cluster closes at the evaporation field strength signaling fieldinduced metallization of the insulator. Following the structural changes in the cluster at the evaporation field strength, we can identify the field evaporated species, in particular, we show that the most abundant ion, Zn ^{2+}, is NOT postionized but leaves the surface as 2+ largely confirming the experimental observations. Our results also help to explain problems related to stoichiometry in the mass spectra measured in atom probe tomography.

Numerical simulations of hysteretic ac losses in a tubular superconductor/paramagnet heterostructure subject to an oscillating transverse magnetic field are performed within the quasistatic approach, calling upon the COMSOL finiteelement software package and exploiting magnetostaticelectrostatic analogues. It is shown that onesided magnetic shielding of a thin, typeII superconducting tube by a coaxial paramagnetic support results in a slight increase of hysteretic ac losses as compared to those for a vacuum environment, when the support is placed inside; a spectacular shielding effect with a possible reduction of hysteretic ac losses by orders of magnitude, however, ensues, depending on the magnetic permeability and the amplitude of the applied magnetic field, when the support is placed outside.

We determined the spintransport properties of Pd and Pt thin films by measuring the increase in ferromagnetic resonance damping due to spinpumping in ferromagnetic (FM)nonferromagnetic metal (NM) multilayers with varying NM thicknesses. The increase in damping with NM thickness depends strongly on both the spin and chargetransport properties of the NM, as modeled by diffusion equations that include both momentum and spinscattering parameters. We use the analytical solution to the spindiffusion equations to obtain spindiffusion lengths for Pt and Pd. By measuring the dependence of conductivity on NM thickness, we correlate the charge and spintransport parameters, and validate the applicability of various models for momentumscattering and spinscattering rates in these systems: constant, inverseproportional (DyakanovPerel), and linearproportional (ElliotYafet). We confirm previous reports that the spinscattering time appears to be shorter than the momentum scattering time in Pt, and the DyakanovPerellike model is the best fit to the data.