Spin-polarized Wannier functions for the two-dimensional topological insulators Zheng-Wei Zuo, Dong-Bo Ling, Yunyou Yang, L. Sheng and D. Y. Xing EPL, 111 5 (2015) 50002 Published online: 15 September 2015 DOI: 10.1209/0295-5075/111/50002