Dr. Shubhayu Chatterjee, University of California, Berkeley

"Skyrmion pairing: a topological route to superconductivity"

Abstract: Atomically thin Van der Waals materials have emerged as a highly versatile platform to advance our understanding of quantum matter driven by strong electron correlations. Recent experimental breakthroughs in stabilizing few-layered graphene structures with a “magic” relative twist between layers has led to the discovery of a wide variety of correlated states ranging from magnetism to superconductivity on the one hand, and opportunities to develop new experimental techniques to probe physics at a distinct emergent length scale on the other. Despite compelling experimental evidence for unconventional superconductivity, the glue which binds electrons into Cooper pairs and the symmetry of the pair wave-function remain unresolved. In this talk I will propose a novel resolution: the Cooper pairs are composed of electrically charged topological spin textures called “skyrmions,” rather than electrons. First proposed by Tony Skyrme to model baryons in particle physics, I will explain how their topological properties can give rise to superconductivity in an electronic model with purely repulsive interactions, and without recourse to phonons which are conventionally responsible for pairing. Finally, I will also demonstrate how magnetic noise detected via proximate single-spin qubit probes can be used to diagnose the pairing symmetry of the superconductor.