Carrier mobilities of Janus transition metal dichalcogenides monolayers studied by Born effective charge and first-principles calculation

Two-dimensional (2D) Janus transition metal dichalcogenides (TMDs) are a new class of materials with unique physical properties. However, the carrier mobility of most Janus TMDs calculated by deformation potential theory (DPT) is not reliable due to the unconsidered part of lattice scattering. In this work, we propose a new method of Born effective charge (BEC) to calculate the carrier mobility of Janus TMDs by including the important factors that neglected in the DPT. The BEC could be used in the calculation of both pure and defective Janus TMDs by employing density functional perturbation theory. We have figured out the relationship between the carrier mobility and the value of BEC, which is the lower the absolute BEC, the higher the electron or hole mobility. Using the new method, we have calculated the carrier mobility of commonly studied Janus TMDs with and without defect. The method may shed light on the high-throughout calculation of selecting high carrier mobility 2D materials.