Anisotropic magnetoresistance of GaAs two-dimensional holes

TL;DR

This study investigates how the in-plane magnetic field's direction affects the magnetoresistance in high-quality GaAs two-dimensional holes, revealing anisotropic behaviors linked to band structure and spin-subbands.

Contribution

It provides a detailed analysis of the anisotropic magnetoresistance in GaAs 2D holes, considering band structure and spin effects, which was not thoroughly explored before.

Findings

Magnetoresistance depends on magnetic field orientation.

The insulator transition point varies with field direction.

Anisotropic band structure influences magnetoresistance behavior.

Abstract

Experiments on high-quality GaAs (311)A two-dimensional holes at low temperatures reveal a remarkable dependence of the magnetoresistance, measured with an in-plane magnetic field ($B$), on the direction of $B$ relative to both the crystal axes and the current direction. The magnetoresistance features, and in particular the value of $B$ above which the resistivity exhibits an insulating behavior, depend on the orientation of $B$. To explain the data, the anisotropic band structure of the holes and a re-population of the spin-subbands in the presence of $B$, as well as the coupling of the orbital motion to $B$, need to be taken into account.