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

Abstract

Based on density functional theory and Berry curvature calculations, we predict that p-p band inversion type quantum spin Hall effect (QSHE) can be realized in a series of two dimensional (2D) bilayer honeycomb TlM (M = N, P, As, Sb), which can be effectively equivalent to bilayer triangular lattice for low energy electrons. Further topological analysis reveals that the band inversion between p − z and px,y of M atom contributes to the nontrivial 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 triangle 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 local band gap of the systems can reach 550 meV (TlSb), which provides a new choice for future room temperature quantum spin Hall Insulator (QSHI). Considering the advance of the technology of van der Waals passivation, combining with hexagonal materials, such as h-BN, TlMs show great potential for future 2D topological electronic devices.

Bonding, structure, and mechanical stability of 2D materials: the predictive power of the periodic table

“…Table 6 contains the cohesive energies and structural data of the groups of related monolayers BX, 131,[136][137][138][139][140][141][142] AlX, 131,142,143 GaX, 131,134,142,144,145 InX, 131,134,142,146,147 and TlX 131,148 with X = N, P, As, Sb, and Bi. As revealed in Fig.…”

“…For bilayer honeycomb Tl compounds a p-p band inversion type QSH effect was predicted that is independent of SOP. 148 Planar h-BN, with its strong bonding and large band gap, seems to be the best insulator and is particularly attractive as the ultimately thin insulator, barrier, or encapsulant. It is chemically inert and resistant to oxidation up to elevated temperatures and to corrosion.…”

Coexistence of giant Rashba spin splitting and quantum spin Hall effect in H–Pb–F

“…The 2D QSHE has potential applications in topological spintronic devices because of its one-dimensional edge state protected by time inversion symmetry. At present, a large number of 2D TI have been found experimentally and theoretically, such as hexagonal lattice materials, [17,18] III-V bilayers, [19][20][21] HgX (X = Te, Se), [22] ZrTe 5 /HfTe 5 , [23] triangle lattice systems of Au/GaAs(111) surface and mxenes, [24,25] and transition metal halide. [26] However, only a few materials have been proved to have 2D topological edge states by experiments, such as InAs/GaSb [27] and HgTe/CdTe [28] quantum wells, Bi coverd Bi 2 Te 3 .…”

Realization of Opened and Closed Nodal Lines and Four- and Three-fold Degenerate Nodal Points in XPt (X = Sc, Y, La) Intermetallic Compound: A Computational Modeling Study

“…In the last decade, with the discovery of topological insulators (Cava et al, 2013;Kou et al, 2013;Zhao et al, 2013;Shen and Cha, 2014;Wang et al, 2014;Luo et al, 2015;Zhou et al, 2015;Liu et al, 2016;Chen et al, 2017a;Loïc and Izmaylov, 2017;Pan et al, 2017;Pielnhofer et al, 2017;Politano et al, 2017;Andrey et al, 2018;Hu et al, 2018Hu et al, , 2019Gao et al, 2019;Mal et al, 2019;Qiao et al, 2019;Narimani et al, 2020), topologically non-trivial materials have attracted significant interest in the chemistry, physics, and materials science communities. Recently, studies have increasingly focused on topological semimetals/metals (Bin et al, 2018;Chenguang et al, 2018;Zhou et al, 2018;He et al, 2019He et al, , 2020Jin et al, 2019aJin et al, , 2020bLi et al, 2019;Qie et al, 2019;Xie et al, 2019;Yi et al, 2019;Zhong et al, 2019;Ma and Sun, 2020;Meng et al, 2020b;Wang et al, 2020a,c,d;Yang and Zhang, 2020;Zhang et al, 2020;Zhao et al, 2020) with non-trivial band topology.…”