Spin-orbit interaction in monolayer (group-III) metal-monochalcogenides

Beginning with an analysis of the fundamental symmetries of monolayer (group-III) metal-monochalcogenides (such as GaSe), we examine various spin-dependent properties of this new series of 2D semiconductors. Interesting features resulting from spin-orbit interaction include broken valence band degeneracy, cubic Dresselhaus spin splitting, and eigenstate spin-mixing. The latter two control the type and magnitude of dominant spin relaxation pathways and influence the `caldera' shape valence band edge. Further phenomena endowed by spin-orbit interaction include a modest orbital contribution to the Lande g-factors and the possibility of optical orientation via band-edge photoexcitation spectroscopy, which shows an energy-dependent reversal of conduction electron spin polarization. Based on this analysis, we propose an experiment to use optically-driven spin dynamics to quantify different spin lifetimes for electron and holes. Reference: arXiv:1508.06963