Weak antilocalization of holes in HgTe quantum wells with a normal energy spectrum

TL;DR

This study investigates weak antilocalization effects in narrow HgTe quantum wells with hole conductivity, revealing how spin-orbit splitting and energy spectrum features influence phase relaxation and magnetoconductivity behavior.

Contribution

It provides experimental analysis of interference effects in HgTe quantum wells considering strong spin-orbit splitting and nonmonotonic energy spectrum characteristics.

Findings

Phase relaxation time increases with conductivity and decreases with temperature, following 1/T law.

Behavior consistent with inelastic electron-electron interactions as the main phase relaxation mechanism.

Nonmonotonic energy spectrum may cause unusual inelastic interaction channels at higher conductivities.

Abstract

The results of experimental study of interference induced magnetoconductivity in narrow HgTe quantum wells of hole-type conductivity with a normal energy spectrum are presented. Interpretation of the data is performed with taking into account the strong spin-orbit splitting of the energy spectrum of the two-dimensional hole subband. It is shown that the phase relaxation time found from the analysis of the shape of magnetoconductivity curves for the relatively low conductivity when the Fermi level lies in the monotonic part of the energy spectrum of the valence band behaves itself analogously to that observed in narrow HgTe quantum wells of electron-type conductivity. It increases in magnitude with the increasing conductivity and decreasing temperature following the $1/T$ law. Such a behavior corresponds to the inelasticity of electron-electron interaction as the main mechanism of the phase relaxation and agrees well with the theoretical predictions. For the higher conductivity, despite the fact that the dephasing time remains inversely proportional to the temperature, it strongly decreases with the increasing conductivity. It is presumed that a nonmonotonic character of the hole energy spectrum could be the reason for such a peculiarity. An additional channel of the inelastic interaction between the carriers in the main and secondary maxima occurs when the Fermi level arrives the secondary maxima in the depth of the valence.