Interplay between Topological States and Rashba States as Manifested on Surface Steps at Room Temperature

TL;DR

This study demonstrates room-temperature interaction and controllability of Rashba and topological surface states in thin films, revealing a new mechanism for manipulating spin textures crucial for spintronic applications.

Contribution

It provides the first experimental observation of Rashba-topological state interaction at room temperature and shows how layer thickness controls their spin textures.

Findings

Rashba states coexist with topological surface states along surface steps.

Reducing film thickness switches off Rashba edge states.

Spin textures can be manipulated at room temperature using thin film technology.

Abstract

The unique spin texture of quantum states in topological materials underpins many proposed spintronic applications. However, realizations of such great potential are stymied by perturbations, such as temperature and local fields imposed by impurities and defects, that can render a promising quantum state uncontrollable. Here, we report room-temperature observation of interaction between Rashba states and topological surface states, which manifests unique spin textures controllable by layer thickness of thin films. Specifically, we combine scanning tunneling microscopy/spectroscopy with the first-principles theoretical calculation to find the robust Rashba states coexisting with topological surface states along the surface steps with characteristic spin textures in momentum space. The Rashba edge states can be switched off by reducing the thickness of a topological insulator Bi2Se3 to bolster their interaction with the hybridized topological surface states. The study unveils a manipulating mechanism of the spin textures at room temperature, reinforcing the necessity of thin film technology in controlling quantum states.