Carrier mobility predicted by born effective charge in Janus transition metal dichalcogenides monolayers

Abstract

Two-dimensional (2D) Janus transition metal dichalcogenides (TMDs) are a new class of materials with unique electrical properties. The carrier mobility of Janus TMDs calculated by deformation potential theory (DPT) is unreliable because partial lattice scattering is not taken into account. In this work, we propose a new Born Effective Charge (BEC) method to predict the carrier mobility of Janus TMDs by employing density functional perturbation theory, which includes the important factors neglected in DPT. We have figured out the relationship between carrier mobility and BEC value, that is, the lower the absolute BEC value, the higher the carrier mobility of electrons or holes. The carrier mobilities of commonly used defective and defect-free Janus TMDs were calculated by the new method, and the calculated results are in good agreement with the experimental results. This method can be used for high-throughput calculations to select high-carrier mobility 2D materials, and the data provide a practical paradigm for evaluating carrier mobility in 2D TMDs.