title: Robustness of a Topologically Protected Surface State in a Sb2Te2Se Single Crystal.
abstract: A topological insulator (TI) is a quantum material in a new class with attractive properties for physical and technological applications. Here we derive the electronic structure of highly crystalline Sb2Te2Se single crystals studied with angle-resolved photoemission spectra. The result of band mapping reveals that the Sb2Te2Se compound behaves as a p-type semiconductor and has an isolated Dirac cone of a topological surface state, which is highly favored for spintronic and thermoelectric devices because of the dissipation-less surface state and the decreased scattering from bulk bands. More importantly, the topological surface state and doping level in Sb2Te2Se are difficult to alter for a cleaved surface exposed to air; the robustness of the topological surface state defined in our data indicates that this Sb2Te2Se compound has a great potential for future atmospheric applications.
authors.affiliation: Department of Photonics, National Sun Yat-sen University, 70, Lienhei Road, Kaohsiung 80424, Taiwan.|Department of Physics, National Sun Yat-sen University, 70, Lienhei Road, Kaohsiung 80424, Taiwan.
authors.forename: Chao-Kuei
authors.initials: CK
authors.lastname: Lee
authors.affiliation: Department of Physics, National Sun Yat-sen University, 70, Lienhei Road, Kaohsiung 80424, Taiwan.|National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
authors.forename: Cheng-Maw
authors.initials: CM
authors.lastname: Cheng
authors.affiliation: National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
authors.forename: Shih-Chang
authors.initials: SC
authors.lastname: Weng
authors.affiliation: National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
authors.forename: Wei-Chuan
authors.initials: WC
authors.lastname: Chen
authors.affiliation: National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
authors.forename: Ku-Ding
authors.initials: KD
authors.lastname: Tsuei
authors.affiliation: Department of Materials and Optoelectronics Science, National Sun Yat-sen University, 70, Lienhei Road, Kaohsiung 80424, Taiwan.
authors.forename: Shih-Hsun
authors.initials: SH
authors.lastname: Yu
authors.affiliation: Department of Materials and Optoelectronics Science, National Sun Yat-sen University, 70, Lienhei Road, Kaohsiung 80424, Taiwan.
authors.forename: Mitch Ming-Chi
authors.initials: MM
authors.lastname: Chou
authors.affiliation: Department of Physics, National Sun Yat-sen University, 70, Lienhei Road, Kaohsiung 80424, Taiwan.
authors.forename: Ching-Wen
authors.initials: CW
authors.lastname: Chang
authors.affiliation: Department of Physics, National Sun Yat-sen University, 70, Lienhei Road, Kaohsiung 80424, Taiwan.|Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
authors.forename: Li-Wei
authors.initials: LW
authors.lastname: Tu
authors.affiliation: Department of Physics, National Sun Yat-sen University, 70, Lienhei Road, Kaohsiung 80424, Taiwan.
authors.forename: Hung-Duen
authors.initials: HD
authors.lastname: Yang
authors.affiliation: Department of Electrophysics, National Chiao Tung University, Hsinchu 300, Taiwan.
authors.forename: Chih-Wei
authors.initials: CW
authors.lastname: Luo
authors.affiliation: Institute of Solid State Physics, Bulgarian Academy of Sciences, Blvd. TzarigradskoChaussee 72, 1784 Sofia, Bulgaria.
authors.forename: Marin M
authors.initials: MM
authors.lastname: Gospodinov