Special Seminar

Abstract: Exploring and understanding new quantum materials with advanced properties tied to their nontrivial magnetic and electronic structures has been a central focus of modern condensed matter physics over the past few decades. The success of these efforts relies simultaneously on advances in theory, material synthesis, and development of new, sensitive metrology tools to characterize the key material properties at the nanoscale. Nitrogen-vacancy (NV) centers, optically active atomic spin defects in diamond, are naturally relevant in this context due to their single-spin sensitivity, excellent quantum coherence, unprecedented spatial resolution, and remarkable functionality over a broad temperature range. Serving as a local probe of multiple degrees of freedom, NV centers are ideally posed to investigate the fundamental correlations between microscopic magnetic textures and underlying charge, thermal transport properties of quantum materials. In this talk, I will present our recent work on using NV centers to perform quantum sensing and imaging of emergent condensed matter systems. Specifically, we utilized NV wide-field method to probe the exotic spin properties of intrinsic topological magnets and antiferromagnetic Weyl semimetals, revealing the fundamental physics underlying the diffusive spin transport, magnetic phase transitions, spin fluctuations, and spin-current driven magnetic switching behaviors at the nanoscale.

Our results demonstrate the unique capabilities of NV centers in accessing the local information of magnetic order and dynamics in these emergent material systems and suggest new opportunities for investigating the interplay between topology, electron correlations, and magnetism in a broad range of quantum materials.

Short Bio: Hailong Wang is a research scientist at Center for Memory and Recording Research at University of California, San Diego (UCSD). He received his B.S. in physics from East China Normal University in 2010, and Ph.D. in physics from The Ohio State University in 2015. He worked as a postdoctoral fellow at The Pennsylvania State University and Massachusetts Institute of Technology from 2015 to 2019 before joining UCSD. Hailong’s current research focuses on synthesis of quantum materials and developing quantum sensing techniques for studying emergent condensed matter systems.