Weak Electron-Phonon Coupling and Unusual Electron Scattering of   Topological Surface States in Sb(111) by Laser-Based Angle-Resolved   Photoemission Spectroscopy
  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. 
Zhuojin Xie, Shaolong He, Chaoyu Chen, Ya Feng, Hemian Yi, Aiji Liang,   Lin Zhao, Daixiang Mou, Junfeng He, Yingying Peng, ...
cond-mat.str-el cond-mat.mtrl-sci