The successfully experimental fabrication of two-dimensional Te monolayer films[Phys.Rev.Lett.119106101(2017)]has promoted the researches on the group-VI monolayer materials.In this work,the electronic structures and ...The successfully experimental fabrication of two-dimensional Te monolayer films[Phys.Rev.Lett.119106101(2017)]has promoted the researches on the group-VI monolayer materials.In this work,the electronic structures and topological properties of a group-VI binary compound of TeSe_(2) monolayers are studied based on the density functional theory and Wannier function method.Three types of structures,namely,a-TeSe_(2),b-TeSe_(2),and g-TeSe_(2),are proposed for the TeSe_(2) monolayer among which the a-TeSe_(2) is found being the most stable.All the three structures are semiconductors with indirect band gaps.Very interestingly,the g-TeSe_(2) monolayer becomes a quantum spin Hall(QSH)insulator with a global nontrivial energy gap of 0.14 eV when a 3.5%compressive strain is applied.The opening of the global band gap is understood by the competition between the decrease of the local band dispersion and the weakening of the interactions between the Se px,py orbitals and Te px,py orbitals during the process.Our work realizes topological states in the group-VI monolayers and promotes the potential applications of the materials in spintronics and quantum computations.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11574051 and 11874117)Natural Science Foundation of Shanghai,China(Grant No.21ZR1408200).
文摘The successfully experimental fabrication of two-dimensional Te monolayer films[Phys.Rev.Lett.119106101(2017)]has promoted the researches on the group-VI monolayer materials.In this work,the electronic structures and topological properties of a group-VI binary compound of TeSe_(2) monolayers are studied based on the density functional theory and Wannier function method.Three types of structures,namely,a-TeSe_(2),b-TeSe_(2),and g-TeSe_(2),are proposed for the TeSe_(2) monolayer among which the a-TeSe_(2) is found being the most stable.All the three structures are semiconductors with indirect band gaps.Very interestingly,the g-TeSe_(2) monolayer becomes a quantum spin Hall(QSH)insulator with a global nontrivial energy gap of 0.14 eV when a 3.5%compressive strain is applied.The opening of the global band gap is understood by the competition between the decrease of the local band dispersion and the weakening of the interactions between the Se px,py orbitals and Te px,py orbitals during the process.Our work realizes topological states in the group-VI monolayers and promotes the potential applications of the materials in spintronics and quantum computations.
