Evidence for a capacitor network near the metal insulator transition in VO2 thin films probed by in-plane impedance spectroscopy

TL;DR

This study uses in-plane impedance spectroscopy to reveal a capacitor network near the metal-insulator transition in VO2 thin films, showing non-ideal RC behavior and capacitance changes around the transition.

Contribution

It provides new insights into the dielectric response and capacitor network behavior of VO2 thin films near the MIT using impedance spectroscopy.

Findings

Non-ideal RC behavior observed from room temperature to 334 K.

Capacitance decreases near the MIT, possibly due to interface effects.

Capacitance increases around the MIT, indicating a capacitor network formation.

Abstract

Impedance spectroscopy measurements were performed in high quality Vanadium dioxide (VO2) thin films. This technique allows us investigate the resistive and capacitive contribution to the dielectric response near the metal-insulator transition (MIT). A non ideal RC behavior was found in our films from room temperature up to 334 K. A decrease of the total capacitance was found in this region, possibly due to interface effects. Above the MIT, the system behaves like a metal as expected, and a modified equivalent circuit is necessary to describe the impedance data adequately. Around the MIT, an increase of the total capacitance is observed.