Effect of one-dimensional superlattice potentials on the band gap of two-dimensional materials

摘要

Using the tight-binding approach, we analyze the effect of a one-dimensionalsuperlattice (1DSL) potential on the electronic structure of black phosphoreneand transition metal dichalcogenides. We observe that the 1DSL potentialresults in a decrease of the energy band gap of the two-dimensional (2D)materials. An analytical model is presented to relate the decrease in thedirect-band gap to the different orbital characters between the valence bandtop and conduction band bottom of the 2D materials. The direct-to-indirect gaptransition, which occurs under a 1DSL potential with an unequal barrier width,is also discussed.