Breaking a Bloch-wave interferometer: quasiparticle species-specific temperature-dependent nonequilibrium dephasing

TL;DR

This study explores how temperature-dependent dephasing affects high-order sideband generation in gallium arsenide, revealing species-specific dephasing coefficients for different phonon interactions using a novel polarimetry method.

Contribution

It introduces a method to isolate and quantify nonequilibrium dephasing coefficients for different electron-hole pairs and phonon interactions in bulk gallium arsenide.

Findings

Sideband intensities depend strongly on temperature, polarizations do not.

Distinct dephasing coefficients for heavy and light holes with phonons.

Quantitative values for dephasing coefficients related to LO and A phonons.

Abstract

Recently, high-order sideband polarimetry has been established as an experimental method that links the polarization of sidebands to an interference of Bloch wavefunctions. However, the robustness of sideband polarizations to increasing dephasing remains to be explored. Here, we investigate the dependence of high-order sideband generation in bulk gallium arsenide on dephasing by tuning temperature. We find that the intensities of the sidebands, but not their polarizations, depend strongly on temperature. Using our polarimetry method, we are able to isolate the contributions of electron-heavy hole (HH) and electron-light hole (LH) pairs to sideband intensities, and separately extract the nonequilibrium dephasing coefficients associated with the longitudinal optical (LO) phonons and acoustic (A) phonons for each species of electron-hole pair. We find that $\Gamma_{\text{HH},\text{A}} = 6.1 \pm 1.6$ $\mu$eV/K, $\Gamma_{\text{LH},\text{A}} < 1.5$ $\mu$eV/K, $\Gamma_{\text{HH},\text{LO}} = 14 \pm 3$ meV, and $\Gamma_{\text{LH},\text{LO}} = 30 \pm 3$ meV.