Electrostatic Potential Anomaly in 2D Janus Transition Metal Dichalcogenides

Abstract

AbstractSymmetry breaking induced exotic physical properties is an eternal topic in scientific community. Due to lack of mirror symmetry, 2D Janus transition metal dichalcogenides (TMDs) exhibit many bizarre features; however, the physical mechanisms of most of these intrinsic properties are still unclear. Herein, a generalized and effective approach is developed to disclose the physical mechanism of electrostatic potential anomaly in 2D Janus TMDs, based on fast Fourier transform and Moore–Penrose generalized inverse matrix for separating Hartree potential and ionic potential from electrostatic potential, and conversely, calculating charge density distribution through Hartree potential. Through extensive numerical simulations and theoretical analyses, the electrostatic potential anomaly is expounded successfully, which is a pending issue in 2D Janus TMDs: the electrostatic potential energy at Se atomic layer is larger than that at S and Te atomic layers, which breaks the periodic law. Such an anomaly could be attributed to the competition between Hartree potential energy and ionic potential energy that emerges as a result of asymmetric charge transfer, atomic layer distance, and atomic species. This approach possesses universality, and is proved to be a robust method in dealing with the issues related to electrostatic potential.