Torsion control of the electronic and optical properties of monolayer WS2: A first-principles study

The paper systematically investigates the effects of torsional deformation for monolayer graphene-like transition metal disulfide-WS2 using first-principles calculations. It demonstrates that the geometrical, electronic, and optical properties are influenced distinctively by torsion. The electronic structure analysis reveals that torsion can regularly manipulate the energy level. Torsion improves the intrinsic absorption long-wave cutoff wavelength from 0.639 ?m to 0.850 ?m. In addition to studying the effect of torsion on the optical properties of monolayer WS2, dielectric function, absorption coefficient, reflectivity, and loss function are analyzed. The absorption edge threshold, maximum absorption coefficient, and reflectivity all decrease with the torsion angle increase. When the torsion angle reaches 20?, the electronic structure and optical properties change significantly due to the original bond fracture. This paper provides new possibilities for designing materials on demand.