2022/09/29 by San‐Dong Guo, Jing-Xin Zhu, Guo, San-Dong +9 · 1 citation
Physics and Astronomy · #FOS: Physical sciences #Magnetic properties of thin films #Materials Science (cond-mat.mtrl-sci) #Quantum and electron transport phenomena #Topological Materials and Phenomena
paper · pdf · doi:10.48550/arxiv.2209.14722
openalex publication_date 2022/09/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The manipulation of the Rashba spin-splitting is crucial for the development of nanospintronic technology. Here, it is proposed that the Rashba spin-splitting can be turned on and off by reversing electric-field direction. By the first-principle calculations, our proposal is illustrated by a concrete example of Janus monolayer RbKNaBi. The designed RbKNaBi possesses dynamical, thermal and mechanical stability, and is a large-gap quantum spin Hall insulator (QSHI) with Rashba spin-splitting near the Fermi level. A small built-in electric field is predicted due to very small electronegativity difference between the bottom and top atoms, which is very key to switch Rashba spin-splitting through the experimentally available electric field intensity. Due to out-of-plane structural asymmetry, the Janus monolayer has distinctive behaviors by applying external electric field E with the same magnitude but different directions (z or -z). Our results reveal that the Rashba energy (ER) and Rashba constant (αR) are increased by the positive E, while a negative E suppresses the Rashba splitting to disappear, and then appears again. In a certain E region (0.15 V/Å to 0.25 V/Å), switching Rashba spin-splitting can be achieved by only reversing electric-field direction. Besides, the piezoelectric strain coefficients d11 and d31 (5.52 pm/V and -0.41 pm/V) are predicted, which are higher than or compared with those of many 2D materials. By piezoelectric effect, the strain can also be used to tune Rashba spin-splitting of RbKNaBi. Moreover, a possible spintronic device is proposed to realize the function of spintronic switch.