Tunneling conductance spectra of normal metal/insulator/superconductor (N/I/S) junctions are calculated to determine the potential of tunneling spectroscopy in investigations of topological superconductivity. Peculiar feature of topological supercond
uctors is the formation of gapless edge states in them. Since the conductance of N/I/S junctions is sensitive to the formation of these edge states, topological superconductivity can be identified through edge-state detection. Herein, the effects of Fermi surface anisotropy and an applied magnetic field on the conductance spectra are analyzed to gather indications that can help to identify the topological nature of actual materials.
We report measurements of noncontact friction between surfaces of NbSe$_{2}$ and SrTiO$_{3}$, and a sharp Pt-Ir tip that is oscillated laterally by a quartz tuning fork cantilever. At 4.2 K, the friction coefficients on both the metallic and insulati
ng materials show a giant maximum at the tip-surface distance of several nanometers. The maximum is strongly correlated with an increase in the spring constant of the cantilever. These features can be understood phenomenologically by a distance-dependent relaxation mechanism with distributed time scales.
