Reviews of topical problems

Spectroscopy of electron—phonon interaction of superconducting point contacts: experimental aspects

B.Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, prosp. Lenina 47, Kharkov, 61103, Ukraine

The recovering procedure 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. The approach proposed takes into account both inelastic scattering, which causes suppression of the excess current in the reabsorption of nonequilibrium phonons by electrons undergoing Andreev reflection (Andreev electrons), and elastic processes associated with the electron—phonon renormalization of the energy spectrum in a superconductor. The results obtained are systematically expounded for both the ballistic contacts, wherein the second derivatives of the I—V curve in the normal state are proportional to the EPI functions, and inhomogeneous contacts (with dirty constrictions and clean banks), whose second derivatives in the normal state are either free of phonon singularities or weakly pronounced.

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Fulltext is also available at DOI: 10.3367/UFNe.2019.11.038693
Keywords: Yanson point-contact spectroscopy, electron—phonon coupling, 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. 63 1072–1091 (2020)
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Received: 7th, August 2019, revised: 23rd, October 2019, 11th, November 2019

Оригинал: Бобров Н Л «Спектроскопия электрон-фононного взаимодействия сверхпроводящих микроконтактов: экспериментальные аспекты» УФН 190 1143–1163 (2020); DOI: 10.3367/UFNr.2019.11.038693

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