Observation of chiral surface excitons in a topological insulator Bi₂Se₃.

ABSTRACT: The protected electron states at the boundaries or on the surfaces of topological insulators (TIs) have been the subject of intense theoretical and experimental investigations. Such states are enforced by very strong spin-orbit interaction in solids composed of heavy elements. Here, we study the composite particles-chiral excitons-formed by the Coulomb attraction between electrons and holes residing on the surface of an archetypical 3D TI, [Formula: see text] Photoluminescence (PL) emission arising due to recombination of excitons in conventional semiconductors is usually unpolarized because of scattering by phonons and other degrees of freedom during exciton thermalization. On the contrary, we observe almost perfectly polarization-preserving PL emission from chiral excitons. We demonstrat

SUBMITTER: Kung HH 

PROVIDER: S-EPMC6410791 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature