Atomic and electronic structure of an alloyed topological insulator, Bi1.5 Sb0.5 Te1.7 Se1.3

Wonhee Ko, Insu Jeon, Hyo Won Kim, Hyeokshin Kwon, Se Jong Kahng, Joonbum Park, Jun Sung Kim, Sung Woo Hwang, Hwansoo Suh

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Abstract

Bi2-x Sbx Te3-y Sey has been argued to exhibit both topological surface states and insulating bulk states, but has not yet been studied with local probes on the atomic scale. Here we report on the atomic and electronic structures of Bi1.5 Sb 0.5 Te1.7 Se1.3 studied using scanning tunnelling microscopy (STM) and spectroscopy (STS). Although there is significant surface disorder due to alloying of constituent atoms, cleaved surfaces of the crystals present a well-ordered hexagonal lattice 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, quasi-particle interference patterns from electron scattering demonstrate that the surface states possess linear dispersion and chirality from spin texture, thus verifying its topological nature. 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.

Original languageEnglish
Article number2656
JournalScientific reports
Volume3
DOIs
Publication statusPublished - 2013

ASJC Scopus subject areas

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    Ko, W., Jeon, I., Kim, H. W., Kwon, H., Kahng, S. J., Park, J., Kim, J. S., Hwang, S. W., & Suh, H. (2013). Atomic and electronic structure of an alloyed topological insulator, Bi1.5 Sb0.5 Te1.7 Se1.3. Scientific reports, 3, [2656]. https://doi.org/10.1038/srep02656