Volume 32, Issue 4, July 2014
Index of content:
- 41st Conference on the Physics and Chemistry of Semiconductor Interfaces (41st PCSI 2014)
32(2014); http://dx.doi.org/10.1116/1.4871760View Description Hide Description
Graphene–insulator–graphene vertical tunneling structures are discussed from a theoretical perspective. Momentum conservation in such devices leads to highly nonlinear current–voltage characteristics, which with gates on the tunnel junction form potentially useful transistor structures. Two prior theoretical treatments of such devices are discussed; the treatments are shown to be formally equivalent, although some differences in their implementations are identified. The limit of zero momentum conservation in the theory is explicitly considered, with a formula involving the density-of-states of the graphene electrodes recovered in this limit. Various predictions of the theory are compared to experiment.
Revealing optically induced magnetization in SrTiO3 using optically coupled SQUID magnetometry and magnetic circular dichroism32(2014); http://dx.doi.org/10.1116/1.4871691View Description Hide Description
In this work, the authors study the time- and temperature-dependence of optically induced magnetization in bulk crystals of slightly oxygen-deficient SrTiO3–δ using an optically coupled superconducting quantum interference device magnetometer. Circularly-polarized sub-bandgap light is found to induce a weak (∼5 × 10−7 emu) but extremely long-lived (hours) magnetic moment in SrTiO3–δ at zero magnetic field. The authors utilize this effect to demonstrate that SrTiO3–δ crystals can be used as an optically addressable magnetic memory by writing and subsequently reading magnetic patterns with light. The induced magnetization is consistent with that of a polarized ensemble of independent oxygen-vacancy-related complexes, rather than from collective or long-range magnetic order.