Effect of electric field on the electronic structure and switching behavior of MoS2/Au(111) heterostructures

The recent emergence of two-dimensional (2D) materials, accompanied by rapid advancements in control over vdW stacking of 2D materials has opened numerous alternatives toward engineering diverse vdW heterostructures for various electronic and photonic applications. Previous experimental work indicate that MoS2/Au-based vertical heterojunctions show I-V hysteresis. This finding indicates that these junctions have potential application in memory devices such as memristors and advanced neuromorphic logic circuits. However, the underlying mechanisms behind the resistive switching, the asymmetry of the hysteresis loop, and the corresponding charge transfer processes are not well understood. In this study, we use density functional theory to explore the effect of the applied electric field on the structural and electronic behavior of MoS2/Au(111)-based heterostructures. Our study indicates that the applied electric field modulates the interfacial dipole moments, as well as the polarization within the MoS2 layer, which can explain characteristics of different regions of the polarization-voltage hysteresis loop in these devices. We will also discuss the effects of structural asymmetry of the heterostructure and of point defects on ferroelectric characteristics of the system such as coercive voltage, remnant polarization and dissipation ratio. This study will help pave the way for a comprehensive, atomistic understanding of resistive switching for next-generation computing and memory devices.