External field control and characteristic quantities of Rashba spin orbit coupling in MA 2 Z 4 derived monolayer materials

Abstract

Controllable modulation of Rashba spin-orbit coupling (RSOC) in two-dimensional (2D) quantum systems remains a key challenge in advancing next-generation spintronic devices. Taking MoSi2N4 as a prototype, this study designs a series of 2D semiconductors with significantly enhanced RSOC by strategically incorporating heavy elements and applying structural engineering techniques. Results demonstrate that substituting C and Bi at the A and Z sites in the MoSi2N4 framework efficiently activates substantial RSOC. Further structural modifications to the MXAZ2 system yield even stronger RSOC strength (αR), with values such as 2.09 eVÅ in HfTeCAsBi. Detailed characteristic analysis indicates that there is a strong correlation between the work function difference (ΔΦ), the dipole moment (μ) and αR. External field modulation show that biaxial strain, uniaxial strain, and out-of-plane electric fields can dynamically adjust αR through lattice distortion and interfacial charge redistribution. Additionally, the short channel length of HfSeCAsBi-based spin field-effect transistors (s-FETs) provides significant advantages for high-density device integration. This work can offer valuable theoretical insights for band engineering in high-performance spintronic applications.