标题：Prediction of large-gap quantum spin hall insulator and Rashba-Dresselhaus effect in two-dimensional g-TlA (A = N, P, As, and Sb) monolayer films
作者：Li, Xinru; Dai, Ying; Ma, Yandong; Wei, Wei; Yu, Lin; Huang, Baibiao
作者机构：[Li Xinru] School of Physics, Shandong University, Jinan, Shandong 250100, China.;[Dai Ying] School of Physics, Shandong University, Jinan, Shandong 2 更多
通讯作者地址：[Dai, Y]Shandong Univ, Sch Phys, Jinan 250100, Peoples R China.
关键词：two-dimensional monolayers; topological insulators; quantum spin Hall; effect; Rashba-Dresselhaus effect; density functional theories
摘要：A new family of two-dimensional (2D) topological insulators (TIs) comprising g-TlA (A = N, P, As, and Sb) monolayers constructed by Tl and group-V elements is predicted by first-principles calculations and molecular-dynamics (MD) simulations. The geometric stability, band inversion, nontrivial edge states, and electric polarity are investigated to predict the large-gap quantum spin Hall insulator and Rashba-Dresselhaus effects. The MD results reveal that the g-TlA monolayers remain stable even at room temperature. The g-TlA (A = As, Sb) monolayers become TIs under the influence of strong spin-orbit couplings with large bulk bandgaps of 131 and 268 meV, respectively. A single band inversion is observed in each g-TlA (A = As, Sb) monolayer, indicating a nontrivial topological nature. Furthermore, the topological edge states are described by introducing a sufficiently wide zigzag-nanoribbon. A Dirac point in the middle of the bulk gap connects the valence- and conduction-band edges. The Fermi velocity near the Dirac point with a linear band dispersion is similar to 0.51 x 10(6) m/s, which is comparable to that of many other 2D nanomaterials. More importantly, owing to the broken inversion symmetry normal to the plane of the g-TlA films, a promising Rashba-Dresselhaus effect with the parameter up to 0.85 eV center dot is observed in the g-TlA (A = As, Sb) monolayers. Our findings regarding 2D topological g-TlA monolayers with room-temperature bandgaps, intriguing topological edge states, and a promising Rashba-Dresselhaus effect are of fundamental value and suggest potential applications in nanoelectronic devices.