Spin texture of an irradiated warped topological insulator surface

TL;DR

This paper explores how off-resonant circularly polarized light alters the spin texture of warped topological insulator surfaces, revealing novel spin-momentum locking features influenced by crystal symmetry, with implications for spintronics.

Contribution

It introduces a theoretical framework for understanding and predicting non-trivial spin textures induced by light on warped topological insulator surfaces, extending to similar 2D systems.

Findings

Spin texture breaks conventional spin-momentum locking.

The spin texture is dictated by crystal symmetry.

Proposes an experimental approach to realize these spin textures.

Abstract

Topological insulator is a new state of matter which exhibits exotic surface electronic properties. Determining the spin texture of this class of material is of paramount importance for understanding its topological order and can lead to potential applications in spintronics. Here, we have investigated the nature of the surface state of the topological insulator with hexagonal warping subjected to an off-resonant circularly polarized light. The resulting electronic ground state exhibits a novel feature of spin texture breaking the conventional spin-momentum locking present on a topological insulator surface. The observed spin texture is shown to be a consequence of the symmetry group of the underlying crystal. The generalisation of our method to the other 2D graphene-like systems are straightforward. Our calculation charts a simple experimental route for a realisation of the non-trivial spin-textures.