Spectroscopy of electron-phonon interaction of superconducting point contacts: experimental aspects
N.L. Bobrov B.Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, prosp. Lenina 47, Kharkov, 61103, Ukraine
The recovering procedure functions of the electron-phonon interaction (EPI) functions from the additional nonlinearities of the current-voltage curve ($I-V$ curve) of point contacts associated with an excess current is considered. This took into account both inelastic scattering processes causing suppression of excess current during reabsorption of nonequilibrium phonons by electrons experiencing Andreev reflection (Andreev electrons), and elastic scattering processes associated with electron-phonon renormalization of the superconductor energy spectrum. Results are consistently described both for ballistic contacts, the second derivatives of the $I-V$ curve of which are normally proportional to the functions of EPI, and for inhomogeneous contacts (with dirty narrowing and clean banks), in which the second derivatives have no phonon features or are poorly expressed on the second derivatives.
Keywords: Yanson point contact spectroscopy, electron-phonon interaction, superconductivity, energy gap, excess current PACS:73.40.Jn, 74.25.Kc, 74.45.+c, 74.50.+r (all) DOI:10.3367/UFNe.2019.11.038693 Citation: Bobrov N L "Spectroscopy of electron-phonon interaction of superconducting point contacts: experimental aspects" Phys. Usp., accepted
Received: 7th, August 2019, revised: 23rd, October 2019, accepted: 11th, November 2019