Mechanically Strained Tuning of the Electronic and Dielectric Properties of Monolayer Honeycomb Structure of Tungsten Disulphide (WS2)

First principle calculations have been performed to investigate the influence of mechanical strains on the electronic and dielectric properties of monolayer honeycomb structure of WS2. Our results reveal that mechanical strains reduce the band gap causing a direct-indirect band gap and semiconductor-metal transitions. These transitions, however, depends on the types of applied strain. Assymmetrical biaxial strain has been found to retain the identity of WS2 as a direct band gap semiconductor for 13% value of strain. Imaginary part of dielectric function (epsilon(2)) shows red-shift in the structure peak energy with applied strains. Static dielectric constant (epsilon(s)) has been found to have significant dependence on the type of applied strain.