High-Density Well-Aligned Dislocations Introduced by Plastic Deformation in Bi1−xSbx Topological Insulator Single Crystals

Crystals

卷:9

Riku Fujiwara¹  Keiichi Edagawa¹  Yuki Tokumoto¹ 

[1] Institute of Industrial Science, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8505, Japan;

关键词: topological insulators;    bismuth antimony;    single crystals;    dislocations;    transmission electron microscopy;   

DOI  :  10.3390/cryst9060317

来源: DOAJ

【 摘 要 】

Topological insulators (TIs) have a bulk bandgap and gapless edge or surface states that host helically spin-polarized Dirac fermions. Theoretically, it has been predicted that gapless states could also be formed along dislocations in TIs. Recently, conductivity measurements on plastically deformed bismuth antimony (Bi_1−xSb_x) TIs have revealed excess conductivity owing to dislocation conduction. For further application of them, fundamental study on dislocations in TIs is indispensable. Dislocations controlled based on fundamental studies could potentially be useful not only for experimental investigations of the dislocation properties but also for diverse device applications. In the present study, Bi_1−xSb_x TI single crystals were fabricated by a zone-melting method. The crystals were plastically deformed at room temperature. The resultant dislocations were observed by transmission electron microscopy (TEM). It was found that high-density dislocations with the Burgers vector satisfying the condition for the formation of gapless states were successfully introduced. The dislocations were mostly of edge type with lengths on the order of more than a few micrometers.

【 授权许可】

Unknown