Robustness of topological protected surface state in Sb2Te2Se topological insulator
C.-M. Cheng1*, C.M. Tu2, W.-C. Chen1, J.-Y. Yuh1, K.-D. Tsuei1, M. Gospodinov3, C.W. Luo2
1National Synchrotron Radiation Research Center, Hsinchu, Taiwan
2Department of Electrophysics, National Chiao-Tung University, Hsinchu, Taiwan
3Institute of Solid State Physics, Bulgarian Academy of Science, Sofia, Bulgaria
* presenting author:鄭澄懋,
Topological insulator (TI) is a new class of quantum materials with attractive properties for physics and technological applications owing to their potential in spintronic devices. A crucial problem is that the robustness of topological surface state under ambient environment or gas condemnations. In prototypical topological insulators, such as Bi2Se3 and Bi2Te3, the Dirac point of topological surface state shifts to high binding energy and the bulk conduction band behaves stronger band bending owing to exposed in ambient environment. Here, we report a high resolution angle-resolved photoemission spectroscopy (ARPES) measurement in p-type Sb2Te2Se ternary topological insulator. Several environments, such as air, H atom and alkali-doped, were conducted to study the behavior of topological surface state. Only few changes of the surface state in presented environment reveal the strong robustness of topological order in Sb2Te2Se topological insulator. This finding provides a chance to understand the surface properties of topological insulators after combining ARPES and transport results.

Keywords: topological insulator, ARPES, surface state