Fabrication and characterisation of high-temperature superconducting nanobridges using a thermal scanning probe

In this letter, we demonstrate for the first time the creation of superconducting weak link nanojunctions using a thermal scanning probe to directly create nano-constrictions into YBa2Cu3O7-δ (YBCO) thin film microbridges. Our method effectively reduces the critical current (I_c) over an order of magnitude. The resulting nanobridges exhibit transport and magnetic-field dependence that are consistent with weak-link behavior, suggestive of Josephson-like nanojunctions. This approach provides a novel and flexible method for scaling up quantum mechanical circuits that operate at liquid nitrogen temperatures. Additionally, it offers a promising pathway for modifying properties of the junctions in-situ and post fabrication.