Cyclotron effective mass of 2D electron layer at GaAs/AlGaAs heterojunction subject to in-plane magnetic fields

TL;DR

This study investigates how in-plane magnetic fields distort the Fermi contours of a 2D electron gas at a GaAs/AlGaAs interface, leading to an increase in the cyclotron effective mass confirmed by experimental measurements and theoretical calculations.

Contribution

It provides the first detailed experimental and theoretical analysis of Fermi contour distortion and effective mass increase under in-plane magnetic fields in this heterostructure.

Findings

Fermi contours deviate from circular shape under in-plane magnetic fields.

Cyclotron effective mass increases by up to 5% with in-plane magnetic field.

Experimental results agree with self-consistent theoretical calculations.

Abstract

We have found that Fermi contours of a two-dimensional electron gas at $\rmGaAs/Al_xGa_{1-x}As$ interface deviate from a standard circular shape under the combined influence of an approximately triangular confining potential and the strong in-plane magnetic field. The distortion of a Fermi contour manifests itself through an increase of the electron effective cyclotron mass which has been measured by the cyclotron resonance in the far-infrared transmission spectra and by the thermal damping of Shubnikov-de Haas oscillations in tilted magnetic fields with an in-plane component up to 5 T. The observed increase of the cyclotron effective mass reaches almost 5 \% of its zero field value which is in good agreement with results of a self-consistent calculation.