Localization and electron-electron interaction effects in magnetoresistance of p-type Ge/Ge_{1-x}Si_x heterostructures

TL;DR

This study investigates the magnetoresistance and conductivity in p-type Ge/GeSi heterostructures, revealing the interplay of weak localization and electron-electron interactions affecting their quantum corrections.

Contribution

It provides experimental analysis of quantum correction contributions in strained Ge/GeSi heterostructures, highlighting the role of multiple hole subbands in magnetoresistance behavior.

Findings

EEI contribution is approximately 2/3 of total quantum correction.

WL contribution is approximately 1/3 of total quantum correction.

Magnetoresistance behavior varies with magnetic field and temperature, indicating subband effects.

Abstract

We report on the results of investigation the conductivity and magnetoresistance (MR) temperature dependencies for the two strained multilayer p-type Ge/Ge_{1-x}Si_x heterostructures. The usual logarithmic temperature dependencies for zero magnetic field conductivity due to the weak localization (WL) and electron- electron interaction (EEI) effects take place in both samples. For one of the samples the negative MR is observed in a whole range of magnetic fields up to ~1T at T <=12K, but for the other sample the MR transforms from the negative to positive at B >= 0.2T and T >=1.3K. We attribute such a behavior to the interplay of two types of holes due to partial filling of the second subband. Extrapolation of the observed high-field parabolic MR to B = 0 allows to separate WL and EEI contributions to the total quantum corrections to conductivity at B = 0 resulting for both of our structures in that EEI part is ~2/3 and the WL part is ~1/3.