Large gap two dimensional topological insulators: the bilayer triangular lattice TlM (M = N, P, As, Sb)

作者：Zhou, Pan; Xue, Lin; Sun, Lizhong^*

来源：Journal of Materials Chemistry C, 2017, 5(17): 4268-4274.

DOI：10.1039/c7tc00634a

• SPIN HALL INSULATORS
• GRAPHENE
• STATE

Based on density functional theory and Berry curvature calculations, we predict that the p-p band inversion type quantum spin Hall effect (QSHE) can be realized in a series of two dimensional (2D) bilayer honeycomb TlMs (M = N, P, As, Sb), which can be effectively equivalent to a bilayer triangular lattice for low energy electrons. Further topological analysis reveals that the band inversion between p(z)(-) and p(x, y) of the M atom contributes to the non-trivial topological nature of TlM. The band inversion is independent of spin-orbit coupling which is distinctive from conventional topological insulators (TIs). A tight binding model based on a triangular lattice is constructed to describe the QSH states in the systems. Besides the interesting 2D triangular lattice p-p type inversion for the topological mechanism, the maximal 550 meV local band gap (TlSb) and the tunable global band gap of the systems provide a new choice for a future room temperature quantum spin Hall insulator (QSHI). Considering the advance of the technology of van der Waals passivation, combination with hexagonal materials, such as h-BN, enables TlMs to show great potential for future 2D topological electronic devices.

• 出版日期2017-5-7
• 单位湘潭大学; 太原理工大学