Probing Unconventional Superconductivity with Superconductive Scanning Tunneling Microscopy Tips

In most conventional superconductors, spin-singlet electron pairing results in a translationally invariant condensate with spatially uniform superfluid density. However, electron pairs can also form crystalline states such as pair density waves and exist in a spin-triplet state. Furthermore, in multi-band superconductors, multiple superconducting condensates coexist and can display spatially disparate superfluid densities. In this talk, I will present our recent exploration of unconventional superconductivity using superconductive tips in sub-Kelvin scanning tunneling microscopes. I will start by discussing signatures of non-chiral spin-triplet superconductivity via Andreev reflection spectroscopy. I will then discuss our recent results on quantum interference and multi-condensate visualization via Josephson tunneling, all enabled by the use of superconductive tips.