Anisotropy effects on Rashba and topological insulator spin polarized surface states: a unified phenomenological description

TL;DR

This paper presents a unified phenomenological model for spin-polarized surface states in Rashba systems and topological insulators, highlighting the role of anisotropy and a single effective parameter in describing their band structures.

Contribution

It introduces a unified k.p theory-based model that captures anisotropy effects and the interplay between Rashba splitting and hexagonal warping across different topological materials.

Findings

A single effective parameter describes surface band structure changes.

The model unifies trivial and non-trivial topological surface states.

Anisotropy significantly influences Rashba and topological surface states.

Abstract

Spin polarized two-dimensional electronic states have been previously observed on metallic surface alloys with giant Rashba splitting and on the surface of topological insulators. We study the surface band structure of these systems, in a unified manner, by exploiting recent results of k.p theory. The model suggests a different way to address the effect of anisotropy in Rashba systems. Changes in the surface band structure of various Rashba compounds can be captured by a single effective parameter which quantifies the competition between the Rashba effect and the hexagonal warping of the constant energy contours. The same model provides a unified phenomenological description of the surface states belonging to materials with topologically trivial and non-trivial band structures.