Density-functional-theory calculations of electronic band structure of single-crystal and single-layerWS2

Abstract

Electronic band structures of single-crystal and single-layer ${\mathrm{WS}}_2$ are investigated by first-principles calculations based on local-density-functional theory using a plane-wave basis with ultrasoft pseudopotentials. The band structure calculated for the single crystal corresponds very well with experimental data and recent calculations using an augmented-spherical wave basis [A. Klein et al., Phys. Rev. B $64,$ 205416 (2001)]. The calculations for the single layer show that compared to the bulk case no significant structural relaxations of the atomic positions occur. This result is confirmed by the good agreement of our calculated band structures for the single layer with the data from angle-resolved photoemission measurements.