Weak Electron-Phonon Coupling and Unusual Electron Scattering of Topological Surface States in Sb(111) by Laser-Based Angle-Resolved Photoemission Spectroscopy

TL;DR

This study uses laser-based ARPES to investigate Sb(111) surface states, revealing weak electron-phonon coupling, Rashba splitting, and unusual constant electron scattering rates over a broad energy range.

Contribution

It provides high-resolution measurements of Sb(111) surface states, demonstrating weak electron-phonon interaction and unusual scattering behavior not typical in conventional materials.

Findings

Weak electron-phonon coupling in Sb(111) surface states

Observation of Rashba-type band splitting

Constant electron scattering rate over a large energy window

Abstract

High resolution laser-based angle-resolved photoemission measurements have been carried out on Sb(111) single crystal. Two kinds of Fermi surface sheets are observed that are derived from the topological surface states: one small hexagonal electron-like Fermi pocket around $\Gamma$ point and the other six elongated lobes of hole-like Fermi pockets around the electron pocket. Clear Rashba-type band splitting due to the strong spin-orbit coupling is observed that is anisotropic in the momentum space. Our super-high-resolution ARPES measurements reveal no obvious kink in the surface band dispersions indicating a weak electron-phonon interaction in the surface states. In particular, the electron scattering rate for these topological surface states is nearly a constant over a large energy window near the Fermi level that is unusual in terms of the conventional picture.