Formation of Ideal Rashba States on Layered Semiconductor Surfaces Steered by Strain Engineering

TL;DR

This study demonstrates that depositing a monolayer of gold on layered semiconductor surfaces can create ideal Rashba states with large spin splitting inside the substrate's band gap, tunable by strain, enabling potential spintronic devices.

Contribution

The paper introduces a method to realize ideal Rashba states on layered semiconductor surfaces through metal monolayer deposition and strain engineering, which was not previously demonstrated.

Findings

Au monolayer on beta-InSe(0001) hosts ideal Rashba states

Rashba bands are tunable over a wide energy range with strain

System shows potential for strong current modulation in spintronic devices

Abstract

Spin splitting of Rashba states in two-dimensional electron system provides a promising mechanism of spin manipulation for spintronics applications. However, Rashba states realized experimentally to date are often outnumbered by spin-degenerated substrate states at the same energy range, hindering their practical applications. Here, by density functional theory calculation, we show that Au one monolayer film deposition on a layered semiconductor surface beta-InSe(0001) can possess "ideal" Rashba states with large spin splitting, which are completely situated inside the large band gap of the substrate. The position of the Rashba bands can be tuned over a wide range with respect to the substrate band edges by experimentally accessible strain. Furthermore, our nonequilibrium Green's function transport calculation shows that this system may give rise to the long-sought strong current modulation when made into a device of Datta-Das transistor. Similar systems may be identified with other metal ultrathin films and layered semiconductor substrates to realize ideal Rashba states.