Random-resistor network modeling of resistance hysteresis of vanadium dioxide thin films

Abstract

The resistance hysteresis of vanadium dioxide ([Formula: see text]) is a key feature in revealing mechanisms of a phase transition as well as emerging applications. In this study, a dynamical model based on random-resistor networks is developed to simulate the transport properties of [Formula: see text] thin films. The reversible metal–insulator phase transition of each microscopic domain is captured by a modified Landau-type functional. The proposed model enables analysis of not only the formation of conducting filaments driven by an electric field, but also the thermal-driving reversal curves of resistance hysteresis. It is shown that the appearance of a hysteresis loop as well as the aggregation of metallic domains can be tuned via the interactions of each domain with its neighbors and the substrate. The interaction effects are vital for the persistence of metallic domains, which can re-trigger the insulating-to-metallic transition by a subthreshold voltage bias with the delay time much longer than the transition switching time. These results are in agreement with experimental observations and can be helpful in developing [Formula: see text]-based key components ranging from infrared bolometers to the volatile resistive switches for neuromorphic computing.

Interplay of Thermal and Electronic Effects in the Mott Transition of Nanosized VO2 Phase Change Memory Devices

“…Our electrode-separation-dependent measurements demonstrated the clear decrease of the set voltage with decreasing gap size, which underpins the advantage of the demonstrated confined device geometry with respect to energy consumption. Furthermore, our novel device geometry confines the active region to a rather well-defined spatial spot instead of more complex, percolation-like spatial patterns. − The analysis of the voltage and temperature dependent conduction properties of these devices has pointed out the interplay of local Joule heating and nonlinear transport features in the local insulator-to-metal transition, also indicating a Zener tunneling type conduction mechanism in the high resistance state. Furthermore, the simplified, focused device geometry facilitated the finite element simulation of the device operation.…”

“…These volatile resistive switches exhibit excellent characteristics with stable and reproducible operation up to 10 9 cycles, and simple circuits including one or two VO 2 switches, capacitors, resistors, and batteries can realize artificial neurons that can mimic most of the known biological neuronal dynamic patterns. ,,,, Alternatively, the underlying switching mechanism exhibits remarkable complexity both in the temporal and spatial domains. The former is reflected in the subthreshold switching characteristics for rapidly repeated programming pulses, whereas spatially an inhomogeneous switching region was discovered, where the formation of conductive regions is more pronounced at the device edges. , The description of these phenomena requires complex modeling tools, like a percolation network model. − …”

Resistance fluctuation spectroscopy of phase transitions in (La0.2Pr0.2Nd0.2Sm0.2Eu0.2)NiO3 thin films

“…1(b) is a consequence of the coexistence of metallic and insulating domains due to phase separation. 27 This shows up as an increase in relative variance of noise in PMI phase in cooling run.…”