Two-dimensional topological insulators with large bulk energy gap

Yang Z Q^{1, 2}, Jia Jin-Feng^{1, 2}, Qian Dong^{1, 2, †,}

(a) Top and side views of single-bilayer Bi(111). (b) Calculated energy gap of ultra-thin Bi(111) film as a function of thickness, from Ref. [11]. For single-bilayer Bi(111), the energy gap is larger than 0.5 eV.