Quantum Sensing of Insulator-to-Metal Transitions in a Mott Insulator

TL;DR

This paper demonstrates the use of nitrogen vacancy (NV) centers in diamond for local quantum sensing of insulator-to-metal transitions in Mott insulators, revealing non-thermal transition mechanisms at the nanoscale.

Contribution

It introduces NV-based quantum sensing to directly observe local thermal and electrical behaviors during IMT in Mott insulators, including non-thermal transitions in ion-irradiated VO2.

Findings

NV sensors detect local temperature and magnetic fields during IMT.

Pristine VO2 transitions thermally via Joule heating.

Ion-irradiated VO2 exhibits non-thermal IMT below transition temperature.

Abstract

Nitrogen vacancy (NV) centers, optically-active atomic defects in diamond, have attracted tremendous interest for quantum sensing, network, and computing applications due to their excellent quantum coherence and remarkable versatility in a real, ambient environment. Taking advantage of these strengths, we report on NV-based local sensing of the electrically driven insulator-to-metal transition (IMT) in a proximal Mott insulator. We studied the resistive switching properties of both pristine and ion-irradiated VO2 thin film devices by performing optically detected NV electron spin resonance measurements. These measurements probe the local temperature and magnetic field in electrically biased VO2 devices, which are in agreement with the global transport measurement results. In pristine devices, the electrically-driven IMT proceeds through Joule heating up to the transition temperature while in ion-irradiated devices, the transition occurs non-thermally, well below the transition temperature. Our results provide the first direct evidence for non-thermal electrically induced IMT in a Mott insulator, highlighting the significant opportunities offered by NV quantum sensors in exploring nanoscale thermal and electrical behaviors in Mott materials.