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arXiv · 1503.01006

Two different topological insulator phases in NaBaBi

Yan Sun·Qing-Ze Wang·Shu-Chun Wu·Claudia Felser·Chao-Xing Liu·Binghai Yan
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Abstract

By breaking the inversion symmetry of the three-dimensional Dirac metal Na$_3$Bi, we realize topological insulator (TI) phases in the known compound NaBaBi using $ab~initio$ calculations. Two distinct TI phases emerge: one phase is due to band inversion between the Bi $p$ and Na $s$ bands, and the other phase (under pressure) is induced by inversion of the Bi $p$ and Ba $d$ bands. Both phases exhibit Dirac-cone-type surface states, but they have opposite spin textures. In the upper cone, a left-handed spin texture exists for the $s$-$p$ inverted phase (similar to a common TI, e.g., Bi$_2$Se$_3$), whereas a right-handed spin texture appears for the $p$-$d$ inverted phase. NaBaBi presents a prototype model of a TI that exhibits different spin textures in the same material. In addition, NaBaBi may exhibit the introduction of correlation effects to the topological state owing to the existence of $d$ states in the band inversion.

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Yan Sun, Qing-Ze Wang, Shu-Chun Wu, Claudia Felser, Chao-Xing Liu, Binghai Yan. 2015-03-03. Two different topological insulator phases in NaBaBi. https://doi.org/10.1103/physrevb.93.205303

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