Visualizing Chiral Edge Modes in Twisted Cuprate Superconductors via Scanning-Probe Quantum Sensing

Abstract

Recently, unconventional superconductivity hosted by twisted van der Waals (vdW) heterostructures has received immense interest due to the exotic pairing symmetry, electronic interactions and nontrivial topological nature that are naturally relevant to the fast-advancing quantum technologies. Here, we report scanning-probe quantum sensing of nanoscale electromagnetic behaviors of twisted vdW cuprate superconductors. Using single-spin relaxometry, we directly visualize edge modes spontaneously formed in twisted Bi2Sr2CaCu2O8+x (BSCCO). By investigating temperature dependent variations of edge-state-induced quantum spin relaxation, we experimentally evaluate the magnitude of nontrivial topological band gap opened at nodal points in twisted BSCCO and its critical temperature behaviors under different twist angles. We further observe alternating chiral domains defined by edge modes, exploring experimental signatures of in-plane magnetic field-induced topology in 45° twisted BSCCO. Our results advance the current understanding of twisted vdW nodal superconductors, presenting an appealing high-temperature topological superconducting material platform for cutting-edge quantum innovation.