First-principles study of strain-induced charge polarization in a molybdenum disulfide monolayer

In the presence of elastic planar strain distributions, electronic properties of molybdenum disulfide (M0S2) monolayer are investigated within Density Functional Theory (DFT) calculations as implemented in SIESTA package. Three types of planar strain are considered with some different intensity values, and uniaxial strain along the armchair and zigzag directions as well as biaxial strain. We present a systematic study of the strained M0S2 monolayer by focusing on the calculation of Total Density Of State (TDOS), Partial Density Of State (PDOS), electron charge density, and electrostatic potential using post processing tools. In most cases, the states due to Mo atoms have dominant association in the TDOS close to the Fermi level of M0S2 monolayer under strain. As a consequence of the strain, S atom takes electron from Mo atom and becomes negatively charged. In addition, the tensile and compressive strains introduce the charge polarization in two opposite directions per three types of strain for both sheets, which is in line with the experimental study. As another important result, the strain-induced charge polarization is proportional to the intensity value of strain.