Strain Effects on Rashba Spin-Orbit Coupling of 2D Hole Gases in GeSn/Ge Heterostructures

A demonstration of 2D hole gases in GeSn/Ge heterostructures with a mobility as high as 20 000 cm(2) V-1 s(-1) is given. Both the Shubnikov-de Haas oscillations and integer quantum Hall effect are observed, indicating high sample quality. The Rashba spin-orbit coupling (SOC) is investigated via magneto-transport. Further, a transition from weak localization to weak anti-localization is observed, which shows the tunability of the SOC strength by gating. The magneto-transport data are fitted to the Hikami-Larkin-Nagaoka formula. The phase-coherence and spin-relaxation times, as well as spin-splitting energy and Rashba coefficient of the k-cubic term, are extracted. The analysis reveals that the effects of strain and confinement potential at a high fraction of Sn suppress the Rashba SOC caused by the GeSn/Ge heterostructures.

Automated summary

The demonstration of 2D hole gases in GeSn/Ge heterostructures shows a high mobility of up to 20,000 cm(2) V-1 s(-1). The study observed Shubnikov-de Haas oscillations and integer quantum Hall effect, and investigated the Rashba spin-orbit coupling through magneto-transport. Additionally, a transition from weak localization to weak anti-localization was observed, demonstrating the tunability of SOC strength by gating.