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arXiv · 1906.06528

Cross-band versus intra-band pairing in superconductors: signatures and consequences of the interplay

A. A. Vargas-Paredes·A. A. Shanenko·A. Vagov·M. V. Milošević·A. Perali
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Abstract

We analyze the paradigmatic competition between intra-band and cross-band Cooper-pair formation in two-band superconductors, neglected in most works to date. We derive the phase-sensitive gap equations and describe the crossover between the intraband-dominated and the crossband-dominated regimes, delimited by a ``gapless'' state. Experimental signatures of crosspairing comprise notable gap-splitting in the excitation spectrum, non-BCS behavior of gaps versus temperature, as well as changes in the pairing symmetry as a function of temperature. The consequences of these findings are illustrated on the examples of MgB$_2$ and Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$.

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A. A. Vargas-Paredes, A. A. Shanenko, A. Vagov, M. V. Milošević, A. Perali. 2019-06-15. Cross-band versus intra-band pairing in superconductors: signatures and consequences of the interplay. https://doi.org/10.1103/physrevb.101.094516

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