Search for power-efficient wide-range reversible resistance modulation of $VO_2$ single crystals

TL;DR

This study investigates the electrical behavior of VO2 single crystals during the insulator-metal transition, demonstrating how load resistance and ambient temperature influence power efficiency and stability in resistance modulation.

Contribution

It reveals how steady state resistance modulation in VO2 can be optimized for power efficiency by adjusting load resistance and ambient temperature, avoiding damaging switching.

Findings

Steady state I(V) achieved with high load resistance in NDR regime.

Lower load resistance causes switching and damage to samples.

Increasing ambient temperature reduces power consumption for resistance modulation.

Abstract

The abrupt metal insulator transition in $VO_2$ is attracting considerable interest from both fundamental and applicative angles. We report on DC I-V characteristics measured on $VO_2$ single crystals in the two-probe configuration at several ambient temperatures below the insulator-metal transition. The insulator-mixed-metal-insulator transition is induced by Joule heating above ambient temperature in the range of negative differential resistivity (NDR). In this range the stability of V(I) is governed by the load resistance $R_L$. Steady state I(V) is obtained for $R_L> |dV/dI|_{max}$ in the NDR regime. For $R_L< |dV/dI|_{max}$ there is switching between initial and final steady states associated with peaks in the Joule power, that are higher the lower $R_L$ is. The peaks caused by steep switching are superfluous and damaging the samples. On the other hand, the large $R_L$ needed for steady state is the main power consumer in the circuit at high currents. The present work is motivated by the need to avoid damaging switching in the NDR regime while reducing the power consumption in the circuit. It is shown here that large resistance modulation can be obtained under steady state conditions with reduced power consumption by increasing the ambient temperature of the device above room temperature.