Physics Department - Studying Superconductivity under Pressure using NV Centers

Abstract
Superconductivity was discovered a hundred years ago, yet it is still a vital field in modern physics. However, endless debates about the nature of superconductivity were raised when the community explored deeper. It is technically difficult for certain demanding experiments, and some conventional toolsets with limited resolution and sensitivity will hinder the advancement of the field. In this talk, I will elucidate the advantages of using NV centers as a magnetic probe of the Meissner effect in high-pressure experiments. Phenomenological models are proposed to qualitatively and quantitatively analyze the vector information experienced by NV centers. Critical parameters such as the lower critical fields Hc1, upper critical fields Hc2, and critical current density jc can be extracted from carefully designed magnetic measurements and can be further converted to fundamental parameters such as London penetration depths, coherence length, and superfluid density. This showcases the robustness of the NV centers in studying superconductivity, especially in high-pressure research.