Quantum Theory of Optical Spin Texture in Chiral Tellurium Lattice

TL;DR

This paper develops a microscopic optical bandstructure theory for chiral tellurium, revealing how its lattice induces optical gyrotropy and spin textures, advancing understanding of light-matter interactions in chiral materials.

Contribution

It introduces a deep-microscopic optical bandstructure model for tellurium, linking lattice chirality to optical gyrotropy and spin textures, surpassing semi-classical approximations.

Findings

Degeneracies in optical bandstructure are lifted by tellurium's twisted lattice.

The theory aligns well with experimental optical gyrotropy data.

Chirality manifests as microscopic optical spin texture within the optical wave.

Abstract

The absence of inversion symmetry in chiral tellurium (Te) creates exotic spin textures within its electron waves. However, understanding textured optical waves within Te remains a challenge due to the semi-classical limitations of long-wavelength approximation. To unveil these textured optical waves, we develop a spin-resolved deep-microscopic optical bandstructure for Te analogous to its electronic counterpart. We demonstrate that the degeneracies in this optical bandstructure is lifted by the twisted lattice of Te, which induces optical gyrotropy. Our theory shows excellent agreement with experimental optical gyrotropy measurements. At the lattice level, we reveal that the chirality of Te manifests as deep-microscopic optical spin texture within the optical wave. Our framework uncovers the finite-momentum origin of optical activity and provides a microscopic basis for light-matter interactions in chiral crystalline materials.