We predict that a non-centrosymmetric material NaSnBi locates in a three-dimensional non-trivial topological phase under ambient pressure based on first-principle calculations. By deriving the effective model around the ${\it \Gamma}$ point, we find that the topological phase transition is driven by a Rashba spin-orbital coupling through an odd number of pairs of band touch due to a small anisotropic gap caused by quintic dispersion terms. In contrast to conventional topological insulators, the spin texture of the surface Dirac cone is right-handed and the surface states are strikingly different for different surface terminations.
Lv B Q, Xu N, Weng H M, Ma J Z, Richard P, Huang X C, Zhao L X, Chen G F, Matt C E, Bisti F, Strocov V N, Mesot J, Fang Z, Dai X, Qian T, Shi M and Ding H 2015 Nat. Phys.11 724
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Xu S Y, Belopolski I, Alidoust N, Neupane M, Bian G, Zhang C L, Sankar R, Chang G Q, Yuan Z J, Lee C C, Huang S, Zheng M H, Ma J, Sanchez D S, Wang B K, Bansil A, Chou F C, Shibayev P P, Lin H, Jia S and Hasan M Z 2015 Science349 613
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Lv B Q, Weng H M, Fu B B, Wang X P, Miao H, Ma J, Richard P, Huang X C, Zhao L X, Chen G F, Fang Z, Dai X, Qian T and Ding H 2015 Phys. Rev. X 5 031013
2016, Vol. 33 
