By breaking the inversion symmetry of the three-dimensional Dirac metal Na3Bi, we realize topological insulator (TI) phases in the known compound NaBaBi using abinitio 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., Bi2Se3), 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.
@article{arxiv.1503.01006,
title = {Two different topological insulator phases in NaBaBi},
author = {Yan Sun and Qing-Ze Wang and Shu-Chun Wu and Claudia Felser and Chao-Xing Liu and Binghai Yan},
journal= {arXiv preprint arXiv:1503.01006},
year = {2016}
}