Anisotropic Rashba effect and charge and spin currents in monolayer BiTeI by controlling symmetry

The manipulation of Rashba effects in two-dimensional (2D) electron systems in semiconductors is highly desirable for controllable electronic and optical applications. Here, combining a first-principles investigation and model analysis, we use uniaxial stress to control monolayer BiTeI as a Rashba 2D semiconductor. We find that the stress-driven electron system can be described by an effective anisotropic Rashba model including all three Pauli matrices, and uniaxial stress allows an out-of-plane spin component because of rotational symmetry breaking. When appropriate electron carriers are introduced into the monolayer, an in-plane electric field can induce a charge current and three spin current components (including that based on the out-of-plane spin) because of the reduced symmetry. Therefore, uniaxial stress can be used to control Rashba 2D electron systems such as monolayer BiTeI for promising spintronic devices.