GeSn quantum wells as a platform for spin-resolved hole transport

The nascent group IV GeSn alloys are highly attractive for spintronics applications, including quantum computing, due to their ability to enable highly scalable fabrication and all-electrical spin manipulation. In this work, we conduct an in-depth study of a two-dimensional hole gas in a Ge/GeSn quantum well, exhibiting the integer quantum Hall effect and distinct Shubnikov-de Haas oscillations. Emphasis is given to the determination of the Landé g-factor and its pronounced anisotropy in this two-dimensional system, revealing values significantly higher than those in conventional Ge or SiGe/Ge systems. Moreover, by modeling the spin-orbit interaction using the Iordanskii-Lyanda-Geller-Pikus theory, crucial cubic Rashba spin-orbit interaction coefficients, are extracted and their significance is highlighted. This work provides the experimental validation of the theoretically predicted enhancements in spin-orbit interaction and g-factors in GeSn alloys compared to Ge. Additionally, it delivers essential parameters for the design of hole spin devices, such as hole qubits, utilizing GeSn-based structures on the Si platform. GeSn alloys hold promise for spintronics and quantum computing due to their scalable fabrication and spin manipulation capabilities. Here, the authors study a two-dimensional hole gas in a Ge/GeSn quantum well, revealing enhanced spin-orbit interactions and g-factors, providing key insights for designing GeSn-based spintronic devices.