Linear magnetoresistance due to multiple-electron scattering by low-mobility islands in an inhomogeneous conductor

Linear transverse magnetoresistance is commonly observed in many material systems including semimetals, narrow band-gap semiconductors, multi-layer graphene and topological insulators. It can originate in an inhomogeneous conductor from distortions in the current paths induced by macroscopic spatial fluctuations in the carrier mobility and it has been explained using a phenomenological semiclassical random resistor network model. However, the link between the linear magnetoresistance and the microscopic nature of the electron dynamics remains unknown. Here we demonstrate how the linear magnetoresistance arises from the stochastic behaviour of the electronic cycloidal trajectories around low-mobility islands in high-mobility inhomogeneous conductors and that this process is only weakly affected by the applied electric field strength. Also, we establish a quantitative link between the island morphology and the strength of linear magnetoresistance of relevance for future applications

Nonresonant hydrogen dopants in In(AsN): A route to high electron concentrations and mobilities

We provide evidence for the unique effect of hydrogen on the transport properties of the mid-infrared alloy In(AsN). High electron concentrations and mobilities are simultaneously achieved in hydrogenated In(AsN), and Shubnikov-de Haas oscillations are observed up to near room temperature. These results can be accounted for by the formation of N-H donor complexes with energy levels well above the Fermi energy, far from resonance with the conduction electrons, thus resulting in weak electron scattering even at high donor concentrations. Similar effects should be found in other narrow band gap dilute nitride alloys. © 2013 American Physical Society

Antimonide quantum dot nanostructures for novel photonic device applications

The 3D confinement of carriers in quantum dot (QD) structures offers an attractive alternative compared with bulk or quantum well (QW) structures for optoelectronic devices because of the improved (d-like) density of states (DOS) leading to higher radiative transition rates, narrower spectral linewidth, and the possibility to minimize Auger recombination. This chapter is concerned with the molecular beam epitaxial growth and optical properties of self-assembled InSb and GaSb QDs in InAs and GaAs, respectively. Section 6.2 describes investigations into the growth of InSb on InAs using conventional Stranski-Krastanov growth. In Section 6.3 the structural and optical properties of InSb submonolayer QDs grown using an Sb-As exchange reaction are described, and their performance within a p-i-n LED is evaluated. The growth of GaSb QDs in GaAs is reported in Section 6.4 together with the formation of quantum rings (QRs), and the application of stacks of such GaSb QRs within a solar cell is described in Section 6.5. © 2013 Society of Photo-Optical Instrumentation Engineers (SPIE