Insulator–metal transition characterized by multifunctional diamond quantum sensor

An insulator–metal transition (IMT) is an emergent characteristic of quantum materials, which have a great amount promise for applications, such as memories, optical switches, and analog brain functions. This is due to their ability to switch between two well-defined states. Thus, the characterization of the state-switching process is essential for the application of these materials. For vanadium dioxide ( VO 2), the phase transition can be determined from temperature, magnetic field, and dielectric constant. In this paper, we propose a diamond quantum sensing approach based on nitrogen-vacancy centers for analyzing phase transitions. By using lock-in-based optically detected magnetic resonance and Rabi measurement protocols, temperature and magnetic field can reflect local IMT information of the circuit, and microwave can determine IMT information of an electrical isolation region. Our multifunctional quantum sensor exhibits local, nondestructive, and integrated measurements, which are useful for reliability testing in IMT technology applications.