Novel tunneling technique for measuring electron scattering rates in superconductors: Application to Sn and Sn-In films

Abstract

The low-voltage resistances Rj(T,Is) of low-resistance Sn/Sn-oxide/Cu and Sn0.95In0.05/Sn-In–oxide/Cu tunnel junctions were measured as functions of temperature and supercurrent along the Sn or Sn-In film. From precise numerical fits to a recent theory, we determined the electron-phonon scattering rate at Tc for both Sn and Sn-In to be τe−ph(Tc)−1≊2.8×109s−1±10%, with the assumption of an electron-phonon coupling α2F(ω)∝ω2. We determined that the crystalline anisotropy of the order parameter Δ was proportional to electron mean free path squared, as expected theoretically. Extrapolation to infinite mean free path gave a value for the mean-square anisotropy in Δ in pure Sn of 〈a2〉0=0.0053±13 %. The consistency of these results from sample to sample, and the agreement between all of these results and published theoretical and experimental work, verifies the theory and demonstrates the feasibility of using such measurements to study electron scattering in novel superconducting materials.

Source-reported materials — not catalogue approval

Similar papers