Effective g factor of 2D holes in strained Ge quantum wells

TL;DR

This study measures the effective g-factor of 2D holes in strained Ge quantum wells, revealing a linear decrease with hole density due to valence band non-parabolicity.

Contribution

It provides the first detailed measurement of the perpendicular g-factor of 2D holes in strained Ge quantum wells and links its behavior to band structure effects.

Findings

g-factor decreases linearly with hole density

Valence band non-parabolicity affects g-factor

AC conductivity method effectively measures g-factor

Abstract

The effective g-factor of 2D holes in modulation doped \mbox{p-SiGe/Ge/SiGe} structures was studied. The AC conductivity of samples with hole densities from $3.9 \times 10^{11}$~to $6.2 \times 10^{11}~\text{cm}^{-2}$ was measured in perpendicular magnetic fields up to $8~\text{T}$ using a contactless acoustic method. From the analysis of the temperature dependence of conductivity oscillations, the $\mathrm{g}_{\perp}$-factor of each sample was determined. The $\mathrm{g}_{\perp}$-factor was found to be decreasing approximately linearly with hole density. This effect is attributed to non-parabolicity of the valence band.