title: Quasiparticle Scattering in the Rashba Semiconductor BiTeBr: The Roles of Spin and Defect Lattice Site.
abstract: Observations of quasiparticle interference have been used in recent years to examine exotic carrier behavior at the surfaces of emergent materials, connecting carrier dispersion and scattering dynamics to real-space features with atomic resolution. We observe quasiparticle interference in the strongly Rashba split 2DEG-like surface band found at the tellurium termination of BiTeBr and examine two mechanisms governing quasiparticle scattering: We confirm the suppression of spin-flip scattering by comparing measured quasiparticle interference with a spin-dependent elastic scattering model applied to the calculated spectral function. We also use atomically resolved STM maps to identify point defect lattice sites and spectro-microscopy imaging to discern their varying scattering strengths, which we understand in terms of the calculated orbital characteristics of the surface band. Defects on the Bi sublattice cause the strongest scattering of the predominantly Bi 6p derived surface band, with other defects causing nearly no scattering near the conduction band minimum.
authors.forename: Christopher John
authors.initials: CJ
authors.lastname: Butler
authors.forename: Po-Ya
authors.initials: PY
authors.lastname: Yang
authors.forename: Raman
authors.initials: R
authors.lastname: Sankar
authors.forename: Yen-Neng
authors.initials: YN
authors.lastname: Lien
authors.forename: Chun-I
authors.initials: CI
authors.lastname: Lu
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan.
authors.forename: Luo-Yueh
authors.initials: LY
authors.lastname: Chang
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan.
authors.forename: Chia-Hao
authors.initials: CH
authors.lastname: Chen
authors.forename: Ching-Ming
authors.initials: CM
authors.lastname: Wei
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan.|Taiwan Consortium of Emergent Crystalline Materials (TCECM), National Science Council , Taipei 10622, Taiwan.
authors.forename: Fang-Cheng
authors.initials: FC
authors.lastname: Chou
authors.forename: Minn-Tsong
authors.initials: MT
authors.lastname: Lin
keywords: Rashba semiconductor; defect-dependent scattering; polar surfaces; quasiparticle interference; scanning tunneling microscopy; scanning tunneling spectroscopy