Topologically nontrivial narrow bands in ultrathin SnTe films with defect superstructures

摘要: It is shown that a two-dimensional topological insulator can be realized and the band topology (equivalently, edge states) may further controlled by charge doping in an ultrathin SnTe film with defect superstructure. Based on first-principles density functional theory (DFT), we predict Sn-Te bilayer, if exfoliated from three-dimensional bulk (1 1 1) direction, has trivial its pristine form, but made topologically nontrivial introducing appropriate array of defects. The emergence state ascribed to formation narrow bands near Fermi level spin–orbit splitting defect-induced bands. In addition, demonstrate transition between normal possible under electron or hole which useful for controlling states.