Exploring the change of semiconductor hole mass under Coulomb scattering

TL;DR

This paper investigates how Coulomb scattering affects the effective mass of semiconductor valence holes, considering the mass change during scattering, which has been previously ignored due to its complexity.

Contribution

It derives a detailed model of Coulomb scatterings for valence holes, accounting for mass changes and the underlying semiconductor physics.

Findings

Derived Coulomb scattering expressions from fundamental semiconductor physics.

Highlighted the importance of mass change during hole scattering.

Provided a framework for more accurate many-body hole calculations.

Abstract

Semiconductor valence holes are known to have heavy and light effective masses; but the consequence of this mass difference on Coulomb scatterings has been considered intractable and thus ignored up to now. The reason is that the heavy/light index is quantized along the hole momentum that changes in a Coulomb scattering; so, a heavy hole can turn light, depending on the scattering angle. This mass change has never been taken into account in many-body problems, and a single ``average'' hole mass has been used instead. In order to study the missed consequences of this crude approximation, the first necessary step is to determine the Coulomb scatterings with valence holes in a precise way. We here derive these scatterings from scratch, starting from the threefold valence-electron spatial level, all the way through the spin-orbit splitting, the Kohn-Luttinger effective Hamiltonian, its spherical approximation, and the phase factors that appear when turning from valence electron to hole operators, that is, all the points of semiconductor physics that render valence holes so different from a na\"{i}ve positive charge.