Electrode Assisted Switching in Transition Metal Dichalcogenide-based Memristive Devices

Recent demonstrations of nonvolatile resistive switching (known as memristive behavior) in two-dimensional transition metal dichalcogenides evinced their potential use of these materials in few-atom-thick devices. However, the underlying mechanisms responsible for the observed phenomena and means to control them are yet to be elucidated. In this study, we use first principles calculations within the density functional theory to analyze the electronic structure and charge transport properties in these systems formed by monolayer TMDs and different electrodes. To this end, we compare the impact of different electrodes on the modulation of the junction resistivity. We specifically show that properties of the metal electrodes play a prominent role assisting the semiconductor-to-metal transition between the 1H and 1T' phases in the TMD layer. Our results yield variations in conductivity in agreement with those found in experimental work. Comparison with defective layers indicate that, while certain vacancies or point defects may also increase the conductance in these systems, changes appear to be insufficient to account for the observed enhancement in transport through the semiconducting channel. Nonetheless, vacancies may also lower the transition barrier between the 1H and the 1T' phases in the high-field regime. These results may prove helpful in the optimization of TMD-based memristive devices towards their applications in flexible electronics and neuromorphic computing systems.