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Bethe ansatz approach to thermodynamics of superconducting magnetic alloys

Valery I. Rupasov
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Abstract

We derive thermodynamic Bethe ansatz equations for a model describing an $U\to\infty$ Anderson impurity embedded in a BCS superconductor. The equations are solved analytically in the zero-temperature limit, T=0. It is shown that the impurities depress superconductivity in the Kondo limit, however at T=0 the system remains in the superconducting state for any impurity concentration. In the mixed-valence regime, an impurity contribution to the density of states of the system near the Fermi level overcompensates a Cooper pairs weakening, and superconductivity is enhanced.

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Valery I. Rupasov. 1998-03-03. Bethe ansatz approach to thermodynamics of superconducting magnetic alloys. https://doi.org/10.1103/physrevlett.80.3368

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