Prediction of giant and ideal Rashba-type splitting in ordered alloy monolayers grown on a polar surface

TL;DR

This paper proposes a novel method to achieve giant and ideal Rashba-type spin-orbit splitting in monolayer alloys on polar surfaces, using first-principles calculations to demonstrate its effectiveness for spintronic applications.

Contribution

It introduces a new approach combining ordered alloying and interface engineering to enhance Rashba spin-orbit splitting in 2D materials.

Findings

Both SbBi and PbBi monolayers on Al₂O₃(0001) show giant Rashba splittings.

Energy offsets exceed 600 meV, momentum offsets over 0.3 Å⁻¹.

The strategy offers a tunable way to control spin-orbit effects in low-dimensional materials.

Abstract

A large and ideal Rashba-type spin-orbit splitting is desired for the applications of materials in spintronic devices and the detection of Majorana Fermions in solids. Here, we propose an approach to achieve giant and ideal spin-orbit splittings through a combination of ordered surface alloying and interface engineering, that is, growing alloy monolayers on an insulating polar surface. We illustrate this unique strategy by means of first-principles calculations of buckled hexagonal monolayers of SbBi and PbBi supported on Al$_2$O$_3$(0001). Both systems display ideal Rashba-type states with giant SO splittings, characterized with energy offsets over 600 meV and momentum offsets over 0.3 $\AA^{-1}$, respectively. Our study thus points to an effective way of tuning spin-orbit splitting in low-dimensional materials to draw immediate experimental interest.