Andreev Reflection studies on NbSe₂ with normal and superconducting tip

Tunneling Andreev Reflection (TAR) spectroscopy emerges as a powerful technique for probing superconducting order parameter symmetry in both conventional and unconventional superconductors through decay rate measurements of Andreev process. Unlike traditional Point Contact Andreev Reflection (PCAR), TAR achieves spatial resolution by operating from near-contact to tunneling regimes, enabling local mapping of excess conductance across surface features. This capability is demonstrated through spatial mapping of charge density wave domains in NbSe₂, revealing distinct variations in Andreev reflection signatures. Furthermore, using a NbSe₂ flake-terminated tip to probe the NbSe₂ surface, the study observes characteristic signatures of Josephson currents and subharmonic gap features attributing to multiple Andreev reflections.