Rashba effect modulation in two-dimensional A2B2Te6 (A = Sb, Bi; B = Si, Ge) materials via charge transfer

TL;DR

This study uses first-principles calculations to design and analyze 2D Rashba semiconductors based on A2B2Te6 materials, proposing a new charge transfer-based strategy for modulating the Rashba effect for spintronics applications.

Contribution

It introduces a novel approach to modulate the Rashba effect in 2D materials via charge transfer and adatom surface engineering, expanding the design space for spintronic semiconductors.

Findings

Successfully designed various 2D Rashba semiconductors from A2B2Te6 materials.

Established a quantitative relationship between charge transfer and Rashba constant.

Proposed a practical strategy for Rashba effect modulation using adatoms.

Abstract

Designing two-dimensional (2D) Rashba semiconductors, exploring the underlying mechanism of Rashba effect, and further proposing efficient and controllable approaches are crucial for the development of spintronics. On the basis of first-principles calculations, we here theoretically design all possible types (common, inverse, and composite) of Janus structures and successfully achieve numerous ideal 2D Rashba semiconductors from a series of five atomic-layer A2B2Te6 (A = Sb, Bi; B = Si, Ge) materials. Considering the different Rashba constant {\alpha}R and its modulation trend under external electric field, we comprehensively analyze the intrinsic electric field Ein in terms of work function, electrostatic potential, dipole moment, and inner charge transfer. Inspired by the quantitative relationship between charge transfer and the strength of Ein and even the {\alpha}R, we propose a straightforward strategy of introducing a single adatom onto the surface of 2D monolayer to introduce and modulate the Rashba effect. Lastly, we also examine the growth feasibility and electronic structures of the Janus Sb2Ge2Se3Te3 system and Janus-adsorbed systems on a 2D BN substrate. Our work not only conducts a detailed analysis of A2B2Te6-based Rashba systems, but also proposes a new strategy for efficiently and controllably modulating the {\alpha}R through the reconfiguration of charge transfer.