Shubnikov-de Haas quantum oscillations with large spin splitting in highmobility Al0.8Ga0.2Sb/InAs/ Al0.8Ga0.2Sb quantum-well heterostructures

TL;DR

This study demonstrates high-mobility AlGaSb/InAs quantum wells exhibiting strong spin-orbit coupling, giant magnetoresistance, and observable quantum oscillations, highlighting their potential for topological spintronic applications.

Contribution

The paper reports the epitaxial growth of high-quality AlGaSb/InAs quantum wells with record-high mobility and strong spin-orbit effects, advancing the material platform for spintronic devices.

Findings

Electron mobility of 924,000 cm²/Vs achieved

Pronounced Shubnikov-de Haas oscillations observed up to 30 K

Large effective g-factor of 12.93 indicating strong Zeeman splitting

Abstract

We report the epitaxial growth of high-quality Al0.8Ga0.2Sb-InAs-Al0.8Ga0.2Sb quantum well films featured by high carrier mobility and strong spin-orbit coupling. By appropriately optimizing the Al-to-Ga ratio in the AlGaSb barrier layer, the quantum confinement of the heterostructure is significantlyenhanced, which results in both an ultra-high electron mobility of 924000 cm2/Vs and a giant magnetoresistance ratio of 365000 at low temperatures. Meanwhile, pronounced Shubnikov-deHaas quantum oscillations persist up to 30 K, and their single-frequency feature indicates a well defined Fermi surface without subband mixing in the two-dimensional electron gas channel. Moreover, the large effective g-factor of 12.93 leads to the observation of Zeeman splitting at large magnetic fields. Our results validate the AlGaSb/InAs quantum well heterostructures as a suitable candidate for constructing energy-efficient topological spintronic devices.