A1 Journal article (refereed)
Quasiclassical free energy of superconductors : Disorder-driven first-order phase transition in superconductor/ferromagnetic-insulator bilayers (2020)

Virtanen, P., Vargunin, A., & Silaev, M. (2020). Quasiclassical free energy of superconductors : Disorder-driven first-order phase transition in superconductor/ferromagnetic-insulator bilayers. Physical Review B, 101(9), Article 094507. https://doi.org/10.1103/PhysRevB.101.094507

JYU authors or editors

Publication details

All authors or editors: Virtanen, Pauli; Vargunin, Artjom; Silaev, Mikhail

Journal or series: Physical Review B

ISSN: 2469-9950

eISSN: 2469-9969

Publication year: 2020

Volume: 101

Issue number: 9

Article number: 094507

Publisher: American Physical Society

Publication country: United States

Publication language: English

DOI: https://doi.org/10.1103/PhysRevB.101.094507

Publication open access: Not open

Publication channel open access: 

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/68375

Abstract

n the seminal work by G. Eilenberger, Z. Phys. 214, 195 (1968), a closed-form expression for the free energy of inhomogeneous spin-singlet superconductor in terms of quasiclassical propagators has been suggested. However, deriving this expression and generalizing it for superconductors or superfluids with general matrix structure, e.g., spin-triplet correlations, has remained problematic. Starting from the Luttinger-Ward formulation, we discuss here the general solution. Besides ordinary superconductors with various scattering mechanisms, the obtained free-energy functional can be used for systems, such as superfluid He-3 and superconducting systems with spatially inhomogeneous exchange field or spin-orbit coupling. Using this result, we derive the simplified expression for the free energy in the diffusive and hydrodynamic limits. As an example of using this formalism, we show that impurity scattering restores the first-order phase transition in superconductor-ferromagnetic insulator bilayers making this system similar to the bulk superconductor with the homogeneous built-in exchange field.

Keywords: superconductors; magnets; magnetic fields

Free keywords: Pauli paramagneism; magnetic-field; vortices; equation; vortex; state

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Ministry reporting: Yes

Reporting Year: 2020

JUFO rating: 2