Tunable spin-orbit coupling in two-dimensional InSe

A. Ceferino, S. J. Magorrian, V. Zólyomi, D. A. Bandurin, A. K. Geim, A. Patanè, Z. D. Kovalyuk, Z. R. Kudrynskyi, I. V. Grigorieva, V. I. Fal'ko

Published 2021-06-08Version 1

We demonstrate that spin-orbit coupling (SOC) strength for electrons near the conduction band edge in few-layer $\gamma$-InSe films can be tuned over a wide range. This tunability is the result of a competition between film-thickness-dependent intrinsic and electric-field-induced SOC, potentially, allowing for electrically switchable spintronic devices. Using a hybrid $\mathbf{k\cdot p}$ tight-binding model, fully parameterized with the help of density functional theory computations, we quantify SOC strength for various geometries of InSe-based field-effect transistors. The theoretically computed SOC strengths are compared with the results of weak antilocalization measurements on dual-gated multilayer InSe films, interpreted in terms of Dyakonov-Perel spin relaxation due to SOC, showing a good agreement between theory and experiment.