Impact of ordering on the reactivity of mixed crystals of topological insulators with anion substitution: Bi2SeTe2 and Sb2SeTe2

• Published in: Applied surface science 2021-03, Vol.541, p.148490, Article 148490
• Main Authors: Volykhov, Andrey A., Frolov, Alexander S., Neudachina, Vera S., Vladimirova, Nadezhda V., Gerber, Evgeny, Callaert, Carolien, Hadermann, Joke, Khmelevsky, Nikolay O., Knop-Gericke, Axel, Sánchez-Barriga, Jaime, Yashina, Lada V.
• Format: Article
• Language: English
• Subjects: Mixed crystals; Reactivity; Topological insulators; X-Ray photoelectron spectroscopy
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2020.148490

[Display omitted] •Reactivity of Bi2(Se1-xTex)3 and Sb2(Se1-xTex)3 was studied by in- and ex-situ XPS.•Reactivity of mixed crystals exceeds that of the most reactive binary constituents.•This effect is due to anion ordering which modifies the bond angles. Three-dimensional topological insulators are exotic materials with unique properties. Tetradymite type binary chalcogenides of bismuth and antimony, as well as their mixed crystals, belong to prototypical TIs. Potential device applications of these materials require in-depth knowledge of their stability in the ambient atmosphere and other media maintained during their processing. Here we investigated the reactivity of mixed crystals with anion substitution, Bi2(Se1-xTex)3 and Sb2(Se1-xTex)3, towards molecular oxygen using both in situ and ex situ X-ray photoelectron spectroscopy. The results indicate that, in contrast to cation substitution, partial substitution of tellurium by selenium atoms leads to anomalously high surface reactivity, which even exceeds that of the most reactive binary constituent. We attribute this effect to anion ordering that essentially modifies the bond geometry, especially the respective bond angles as modeled by DFT.