Novel Spin-texture on the warped Dirac-cone surface states in topological insulators

TL;DR

This paper predicts a novel in-plane spin-texture in the warped Dirac surface states of topological insulators, arising from high-order Dresselhaus spin-orbit coupling effects, with implications for spintronic applications.

Contribution

It introduces a new in-plane spin-texture in warped Dirac cones of topological insulators driven by high-order Dresselhaus spin-orbit coupling terms.

Findings

Finite out-of-plane spin component due to surface warping.

Prediction of in-plane spin-texture with spins not perpendicular to momentum.

High-order Dresselhaus terms are essential for this spin-texture.

Abstract

We have investigated the nature of surface states in the Bi2Te3 family of three-dimensional topological insulators using first-principles calculations as well as model Hamiltonians. When the surface Dirac cone is warped due to Dresselhaus spin-orbit coupling in rhombohedral structures, the spin acquires a finite out-of-plane component. We predict a novel in-plane spin-texture of the warped surface Dirac cone with spins not perpendicular to the electron momentum. Our k.p model calculation reveals that this novel in-plane spin-texture requires high order Dresselhaus spin-orbit coupling terms.