Thermal radiative near field transport between vanadium dioxide and silicon oxide across the metal insulator transition

TL;DR

This study measures near-field thermal transport between vanadium dioxide and silicon oxide, revealing a significant change in conductance across the metal-insulator transition, with potential implications for thermal management and phase-change devices.

Contribution

First experimental measurement of near-field thermal transport across vanadium dioxide's metal-insulator transition at submicron distances.

Findings

Conductance contrast exceeds a factor of 2 between phases.

Distance dependence follows a power law trend.

Thermal transport varies with vanadium dioxide's phase state.

Abstract

The thermal radiative near field transport between vanadium dioxide and silicon oxide at submicron distances is expected to exhibit a strong dependence on the state of vanadium dioxide which undergoes a metal-insulator transition near room temperature. We report the measurement of near field thermal transport between a heated silicon oxide micro-sphere and a vanadium dioxide thin film on a titanium oxide (rutile) substrate. The temperatures of the 15 nm vanadium dioxide thin film varied to be below and above the metal-insulator-transition, the sphere temperatures were varied in a range between 100 and 200 Celsius. The measurements were performed using a vacuum-based scanning thermal microscope with a cantilevered resistive thermal sensor. We observe a thermal conductivity per unit area between the sphere and the film with a distance dependence following a power law trend and a conductance contrast larger than 2 for the two different phase states of the film.