Spin-orbit coupling-induced band inversion and spin Chern insulator phase in plumbene and stanene

다국어 초록 (Multilingual Abstract)

Z2 topology in two-dimensional group IVA materials has been explained by the band orders due to the crystal field splitting at the point in the Brillouin zone, while spin-orbit coupling (SOC) was considered just to open a band gap. By using a multi-orbital tight-binding model, we show that the SOC induces band inversion between the conduction and valence bands at the point in plumbene, which also is the case in stanene when the SOC strength increases. As a result of the band inversion, plumbene becomes a spin Chern insulator with a spin Chern number CS = 2 and, as the SOC strength increases, stanene undergoes a topological phase transition from a Z2 topological insulator to a spin Chern insulator with CS = 2. Under a staggered AB-sublattice potential, plumbene undergoes a phase transition from the spin Chern insulator with CS =2 to a Z2 topological insulator with CS =1.

참고문헌 (Reference)

1 H. Pan, "Valley-polarized quantum anomalous Hall effect in silicene" 112 : 106802-, 2014

2 H. Zhao, "Unexpected giant-gap quantum spin Hall insulator in chemically decorated plumbene monolayer" 6 : 20152-, 2016

3 L. Fu, "Topological insulators with inversion symmetry" 76 : 045302-, 2007

4 H. Zhang, "Topological insulators in Bi2Se3, Bi2Te3 and Sb2Te3 with a single Dirac cone on the surface" 5 : 438-, 2009

5 A. Bansil, "Topological band theory" 88 : 021004-, 2016

6 Y. Yang, "Time-reversal-symmetrybroken quantum spin Hall effect" 107 : 066602-, 2011

7 M. Rezaei, "Tight-binding model investigation of the biaxial strain induced topological phase transition in GeCH3" 96 : 085441-, 2017

8 Z. -W. Zuo, "Spin-polarized Wannier functions for the two dimensional topological insulators" 111 : 50002-, 2015

9 L. Sheng, "Spin Chern numbers and time-reversal-symmetry-broken quantum spin Hall effect" 22 : 067201-, 2013

10 J. C. Slater, "Simplified LCAO method for the periodic potential problem" 94 : 1498-, 1954

11 C. -C. Liu, "Quantum spin Hall effect in silicene and two-dimensional germanium" 107 : 076802-, 2011

12 C. L. Kane, "Quantum spin Hall effect in graphene" 95 : 226801-, 2005

13 E. Prodan, "Non-commutative tools for topological insulators" 12 : 065003-, 2010

14 M. Ezawa, "Monolayer topological insulators: silicene, germanene, and stanene" 84 : 121003-, 2015

15 J. Li, "Marginality of bulk-edge correspondence for single-valley Hamiltonians" 82 : 245404-, 2010

16 Y. Xu, "Large-gap quantum spin Hall insulators in tin films" 111 : 136804-, 2013

17 X. -L. Qi, "General theorem relating the bulk topological number to edge states in two-dimensional insulators" 74 : 045125-, 2006

18 C. Si, "Functionalized germanene as a prototype of large-gap two-dimensional topological insulators" 89 : 115429-, 2014

19 X. -L. Yu, "From a normal insulator to a topological insulator in plumbene" 95 : 125113-, 2017

20 X. -L. Yu, "Evolution of the topological properties of two-dimensional group IVA materials and device design" 20 : 2296-, 2018

21 R. Yu, "Equivalent expression of Z2 topological invariant for band insulators using the non-Abelian Berry connection" 84 : 075119-, 2011

22 A. Hattori, "Edge states of hydrogen terminated monolayer materials: silicene, germanene and stanene ribbons" 29 : 115302-, 2017