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Gapless Fermi Surfaces in anisotropic multiband superconductors in magnetic field

V. Barzykin·L. P. Gor'kov
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Abstract

We propose that a new state with a fully gapless Fermi surface appears in quasi-2D multiband superconductors in magnetic field applied parallel to the plane. It is characterized by a paramagnetic moment caused by a finite density of states on the open Fermi surface. We calculate thermodynamic and magnetic properties of the gapless state for both s-wave and d-wave cases, and discuss the details of the 1-st order metamagnetic phase transition that accompanies the appearance of the new phase in s-wave superconductors. We suggest possible experiments to detect this state both in the s-wave (2-H NbSe2) and d-wave (CeCoIn5) superconductors.

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V. Barzykin, L. P. Gor'kov. 2007-02-23. Gapless Fermi Surfaces in anisotropic multiband superconductors in magnetic field. https://doi.org/10.1103/physrevlett.98.087004

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