The Department of Physics presents a seminar by:
Dr. Oleg Rubel
Scientist, Thunder Bay Regional Research Institute
Adjunct Professor, Physics, Lakehead University
Band structure of disordered solids: from localization to high-mobility Kane fermions
Supercells are often used in ab initio calculation in order to model compound alloys, surfaces and defects. One of the main challenges of supercell electronic structure calculations is to recover Bloch character of electronic eigenstates perturbed by a disorder. Here we apply the spectral weight approach to unfolding of the electronic structure of group III-V and II-VI semiconductor solid solutions. The illustrative examples include: formation of localized donor-like states in dilute GaP:N and associated enhancement of its optical activity, direct observation of the valence band anicrossing in dilute GaAs:Bi, and a topological band crossover in ternary (HgCd)Te alloy accompanied by emergence of high-mobility Kane fermions. The analysis facilitates interpretation of optical and transport characteristics of alloys that are otherwise "obscure" in traditional first-principle supercell calculations.
WEDNESDAY, MAY 21, 2014