Dissertation

First-Principles Hyperfine Tensors for GaAs and Si

Philippopoulos, Pericles

2015

Overview

An accurate description of the hyperfine interaction between electron spins and nuclear spins is crucial for understanding spin dynamics in semiconductor nanostructures. In this thesis, we study the hyperfine interactions in III-V semiconductors and Si. We use the Elk code to perform a density-functional-theory calculation of the contact hyperfine parameter for Si and the Ga and As sites in GaAs. Our result differs from the experimental values found with NMR by less than 3%, while the previous theoretical result differs from the same experimental values by more than 10%. To the best of our knowledge, the calculations in this thesis give the first theoretical estimate of the contact hyperfine coupling in GaAs derived from first principles. Additionally, we show how to go beyond usual methods to accurately determine hyperfine tensors in strongly spin-orbit coupled materials. We achieve this by combining density-functional theory and group theory, accounting for the full coupled spin-orbit structure of the associated single-particle states. Finally, we show how to verify the predicted electronic structure experimentally spectroscopically, by determining a set of allowed electric-dipole transitions.

• Publisher: ProQuest Dissertations & Theses
• Subject: Charged particles / Hybridization / Magnetic fields / Nuclear physics / Phosphorus / Quantum dots / Semiconductors / Symmetry
• ISBN: 9798708705396