Surface and bulk Fermiology and band dispersion in non-centrosymmetric BiTeI

TL;DR

This paper uses high-resolution ARPES to distinguish surface and bulk electronic structures in BiTeI, revealing the spin-split bulk bands and confirming the surface state characteristics in a non-centrosymmetric material.

Contribution

It provides detailed experimental separation of surface and bulk electronic structures in BiTeI using UV and soft x-ray ARPES, clarifying the spin structure and Fermi surface shape.

Findings

Surface and bulk states are clearly distinguished in ARPES data.

Spin structures are identical on opposite surfaces, confirming surface state nature.

Bulk Fermi surface has a spindle-torus shape induced by spin-orbit interaction.

Abstract

BiTeI has a layered and non-centrosymmetric structure where strong spin-orbit interaction leads to a giant spin splitting in the bulk bands. Here we present high-resolution angle-resolved photoemission (ARPES) data in the UV and soft x-ray regime that clearly disentangle the surface from the bulk electronic structure. Spin-resolved UV-ARPES measurements on opposite, non-equivalent surfaces show identical spin structures, thus clarifying the surface state character. Soft x-ray ARPES data clearly reveal the spindle-torus shape of the bulk Fermi surface, induced by the spin-orbit interaction.