| AVS 60th International Symposium and Exhibition | |
| Scanning Probe Microscopy Focus Topic | Friday Sessions |
| Session SP+AS+EM+GR+MI+NS+SS-FrM |
| Session: | Probing Electronic and Transport Properties |
| Presenter: | W. Ko, Samsung Advanced Institute of Technology, Republic of Korea |
| Authors: | W. Ko, Samsung Advanced Institute of Technology, Republic of Korea I. Jeon, Samsung Advanced Institute of Technology, Republic of Korea H.W. Kim, Samsung Advanced Institute of Technology, Republic of Korea H. Kwon, Samsung Advanced Institute of Technology, Republic of Korea S.-J. Kahng, Korea University, Republic of Korea J. Park, Pohang University of Science and Technology, Republic of Korea J.S. Kim, Pohang University of Science and Technology, Republic of Korea S.W. Hwang, Samsung Advanced Institute of Technology, Republic of Korea H. Suh, Samsung Advanced Institute of Technology, Republic of Korea |
| Correspondent: | Click to Email |
The alloyed compound Bi2-xSbxTe3-ySey has been argued to exhibit both topological surface states and insulating bulk states, but not yet been studied with local probes on the atomic scale. Here we report on the atomic and electronic structures of Bi1.5Sb0.5Te1.7Se1.3 studied using scanning tunnelling microscopy (STM) and spectroscopy (STS). Although there is significant surface disorder due to the alloying of constituent atoms, cleaved surfaces of the crystals present a well-ordered hexagonal lattice in STM topographs with 10 Å high quintuple layer steps. STS results reflect the band structure and indicate that the surface state and Fermi energy are both located inside the energy gap. In particular, the surface states do not show any electron back-scattering; due to their topological nature they are extremely robust. This finding demonstrates that alloying is a promising route to achieve full suppression of bulk conduction in topological insulators whilst keeping the topological surface state intact.