Ballistic transport in AlAs two-dimensional electrons

TL;DR

This paper reports the observation of commensurability oscillations in an AlAs two-dimensional electron system, revealing details about valley occupation and effective mass anisotropy.

Contribution

It provides experimental evidence of valley-specific oscillations and quantifies the effective mass ratio in AlAs 2D electrons, advancing understanding of their electronic properties.

Findings

Observation of commensurability oscillations in AlAs 2D electrons

Identification of two frequency components corresponding to two valleys

Determination of effective mass ratio m_l/m_t=5.2±0.5

Abstract

We report the observation of commensurability oscillations in an AlAs two-dimensional electron system where two conduction-band valleys with elliptical in-plane Fermi contours are occupied. The Fourier power spectrum of the oscillations shows two frequency components consistent with those expected for the Fermi contours of the two valleys. From an analysis of the spectra we deduce $m_l/m_t=5.2\pm0.5$ for the ratio of the longitudinal and transverse electron effective masses.