Tight-binding theory of surface spin states on bismuth thin films

TL;DR

This paper presents a tight-binding model that explains the surface spin states in bismuth thin films, including their band structure, spin splitting, and spatial penetration, aligning with experimental observations.

Contribution

The study introduces a detailed $sp^3$ tight-binding model that accurately reproduces experimental surface spin phenomena in bismuth thin films.

Findings

The model reproduces the Fermi surface and Rashba spin splitting observed experimentally.

Surface states penetrate a few bilayers near the Brillouin-zone center.

A large out-of-plane spin component is predicted in the surface states.

Abstract

The surface spin states for bismuth thin films were investigated using an $sp^3$ tight-binding model. The model explains the experimental observations using angle-resolved photoemission spectroscopy, including the Fermi surface, the band structure with Rashba spin splitting, and the quantum confinement in the energy band gap of the surface states. A large out-of-plane spin component also appears. The surface states penetrate inside the film to within approximately a few bilayers near the Brillouin-zone center, whereas they reach the center of the film near the Brillouin-zone boundary.