Design rules for modulation-doped AlAs quantum wells

TL;DR

This paper provides systematic design rules for high-quality modulation-doped AlAs quantum wells, enabling better control over their properties and facilitating advanced studies of electron interactions and quantum phenomena.

Contribution

It offers the first comprehensive guidelines for fabricating high-quality AlAs 2DESs based on a wide range of barrier compositions, bridging a gap in sample design knowledge.

Findings

Similar modulation doping mechanisms in AlAs and GaAs

Guidelines for fabricating high-quality AlAs 2DESs

Observation of high-order fractional quantum Hall effects

Abstract

Thanks to their multi-valley, anisotropic, energy band structure, two-dimensional electron systems (2DESs) in modulation-doped AlAs quantum wells (QWs) provide a unique platform to investigate electron interaction physics and ballistic transport. Indeed, a plethora of phenomena unseen in other 2DESs have been observed over the past decade. However, a foundation for sample design is still lacking for AlAs 2DESs, limiting the means to achieve optimal quality samples. Here we present a systematic study on the fabrication of modulation-doped AlAs and GaAs QWs over a wide range of AlxGa1-xAs barrier alloy compositions. Our data indicate clear similarities in modulation doping mechanisms for AlAs and GaAs, and provide guidelines for the fabrication of very high quality AlAs 2DESs. We highlight the unprecedented quality of the fabricated AlAs samples by presenting the magnetotransport data for low density (~1X1011 cm2) AlAs 2DESs that exhibit high-order fractional quantum Hall signatures.