Electrical and optical conductivities of hole gas in $p$-doped bulk III-V semiconductors

TL;DR

This paper derives exact analytical expressions for electrical and optical conductivities of hole gases in p-doped III-V semiconductors, revealing how impurity types and density influence transport properties.

Contribution

It provides the first exact analytical formulas for conductivity and relaxation times in terms of Luttinger parameters, highlighting the role of helicity conservation and impurity potential types.

Findings

Inverse relaxation time differs between heavy and light holes depending on impurity potential.

Drude conductivity increases non-linearly with hole density.

Optical conductivity scales as the square root of frequency and depends on Luttinger parameters.

Abstract

We study electrical and optical conductivities of hole gas in $p$-doped bulk III-V semiconductors described by the Luttinger Hamiltonian. We provide exact analytical expressions of the Drude conductivity, inverse relaxation time for various impurity potentials, Drude weight and optical conductivity in terms of the Luttinger parameters $\gamma_1 $ and $\gamma_2$. The back scattering is completely suppressed as a result of the helicity conservation of the heavy and light hole states. We find that the inverse relaxation time of heavy holes is much less than that of the light holes for Coulomb-type and Gaussian-type impurity potentials and vice-versa for short-range impurity potentials. The Drude conductivity increases non-linearly with the increase of the hole density. The exponent of the density dependence of the conductivity is obtained in Thomas-Fermi limit. The Drude weight varies linearly with the density even in presence of the spin-orbit coupling. The finite-frequency optical conductivity goes as $\sqrt{\omega}$ and its amplitude strongly depends on the Luttinger parameters. The Luttinger parameters can be extracted from the optical conductivity measurement.