Potential energy surface and band gap landscape of molybdenum and titanium disulfides

Abstract

The potential energy surfaces (PESs) and band gap landscapes (BGLs) of MoS 2 and TiS 2 monolayers were studied with a set of density functional methods. For our best knowledge, the PESs for transition metal dichalcogenides as a function of sulfur atom coordinates were studied for the first time. It is found that the energy differences between chemically meaningful points of the PESs are quite stable with respect to the density functional choice. The BGLs are characterized by "wavelike" structure with maxima that refer to 2H forms and minima that refer to 1T forms and ripples between them. It is shown that thermal vibrations may reduce the band gap in 2H form of MoS 2 .