Scanning Tunneling Microscopy and Spectroscopy of UTe₂

Recently, compelling evidence has emerged indicating UTe2 as a heavy-fermion superconductor that exhibits characteristics of a spin-triplet p-wave superconductor, making it an ideal candidate for exploring topological superconductivity. Recently, using a scanning tunnelling microscopy unusual charge density wave (CDW) and pair density wave (PDW) were revealed in UTe₂^1-2. Here we employed <i>s</i>-wave superconducting Nb tips that has introduced scanned Andreev tunnelling microscopy (SATM) for better exploration of topological superconductors such as UTe₂. Through Andreev reflection processes, direct measurement of the topological surface state (TSS) arising from UTe₂'s odd-parity order parameter is possible. This is evidenced by the prominent zero-energy ABS signature at the (0-11) crystal termination observed in conductance measurements. Also, we showed that the step edge of the UTe₂ provides enhancement of the SABS, while the U terminated area does not have zero bias peak at all. Moreover, different cleaved planes in UTe2 were observed.<br/> <br/>Aishwarya, A.<i> et al.</i> Magnetic-field-sensitive charge density waves in the superconductor UTe₂. <i>Nature</i> 618, 928–933 (2023).<br/>Gu, Q. <i>et al.</i> Detection of a pair density wave state in UTe₂. <i>Nature</i> 618, 921–927 (2023).