Electronic, Thermal Expanding, and Optical Absorption Properties of Transition Metal Dichalcogenides: A First-principles Study

A comprehensive investigation was made on the electronic structure, thermal expansion coefficient and light absorption spectrum of total six transition metal dichalcogenides (TMDs) compounds with formula of MX2 (M=Mo, W, Cr, X=S, Se). First, an indirect-direct band gap transition from bulk to singlelayer was declared for all the six compounds. Moreover, the detailed lattice constants and thermal expansion coefficients provided in the paper were the key information for designing MX2-based field effect transistors. Finally, the calculated optical absorption spectra demonstrate that these compounds can effectively utilize solar energy and are good photo catalyst candidates. All these present findings will benefit the design of new generation of novel two-dimensional materials.