title: Mapping polarization induced surface band bending on the Rashba semiconductor BiTeI.
abstract: Surfaces of semiconductors with strong spin-orbit coupling are of great interest for use in spintronic devices exploiting the Rashba effect. BiTeI features large Rashba-type spin splitting in both valence and conduction bands. Either can be shifted towards the Fermi level by surface band bending induced by the two possible polar terminations, making Rashba spin-split electron or hole bands electronically accessible. Here we demonstrate the first real-space microscopic identification of each termination with a multi-technique experimental approach. Using spatially resolved tunnelling spectroscopy across the lateral boundary between the two terminations, a previously speculated on p-n junction-like discontinuity in electronic structure at the lateral boundary is confirmed experimentally. These findings realize an important step towards the exploitation of the unique behaviour of the Rashba semiconductor BiTeI for new device concepts in spintronics.
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Christopher John
authors.initials: CJ
authors.lastname: Butler
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Hung-Hsiang
authors.initials: HH
authors.lastname: Yang
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Jhen-Yong
authors.initials: JY
authors.lastname: Hong
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Shih-Hao
authors.initials: SH
authors.lastname: Hsu
authors.affiliation: 1] Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan [2] Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan.
authors.forename: Raman
authors.initials: R
authors.lastname: Sankar
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Chun-I
authors.initials: CI
authors.lastname: Lu
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Hsin-Yu
authors.initials: HY
authors.lastname: Lu
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Kui-Hon Ou
authors.initials: KH
authors.lastname: Yang
authors.affiliation: National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
authors.forename: Hung-Wei
authors.initials: HW
authors.lastname: Shiu
authors.affiliation: National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
authors.forename: Chia-Hao
authors.initials: CH
authors.lastname: Chen
authors.affiliation: 1] Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan [2] Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan.
authors.forename: Chao-Cheng
authors.initials: CC
authors.lastname: Kaun
authors.affiliation: Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Guo-Jiun
authors.initials: GJ
authors.lastname: Shu
authors.affiliation: 1] Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan [2] National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan [3] Taiwan Consortium of Emergent Crystalline Materials (TCECM), National Science Council, Taipei 10622, Taiwan.
authors.forename: Fang-Cheng
authors.initials: FC
authors.lastname: Chou
authors.affiliation: 1] Department of Physics, National Taiwan University, Taipei 10617, Taiwan [2] Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan.
authors.forename: Minn-Tsong
authors.initials: MT
authors.lastname: Lin