Stability of Bogoliubov Fermi Surfaces within BCS Theory

Abstract

It has recently been realized that the gap nodes of multiband superconductors that break time-reversal symmetry generically take the form of Fermi surfaces of Bogoliubov quasiparticles. However, these Fermi surfaces lead to a nonzero density of states (DOS) at the Fermi energy, which typically disfavors such superconducting states. It has thus not been clear whether they can be stable for reasonable pairing interactions or are in practice preempted by time-reversal-symmetric states with vanishing DOS. In this Letter, we show within BCS theory applied to a paradigmatic model that the time-reversal-symmetry-breaking states are indeed stabilized over broad parameter ranges at weak coupling. Moreover, we introduce a fast method that involves solving the inverse BCS gap equation, does not require iteration, does not suffer from convergence problems, and can handle metastable solutions.

14 pages, 3 figures

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Cited by in corpus (6)

• Identifying Bogoliubov Fermi surfaces via thermoelectric response in a $d$-wave superconductor heterostructure
• Surface density of states and tunneling spectroscopy of a spin-3/2 superconductor with Bogoliubov Fermi Surfaces
• Coexistence of Chiral Majorana Edge States and Bogoliubov Fermi Surfaces in Two-Dimensional Nonsymmorphic Dirac Semimetal/Superconductor Heterostructures
• Discontinuous Transition to Superconducting Phase
• Thermoelectric effect in a superconductor with Bogoliubov Fermi surfaces
• Evolution and Instability of Bogoliubov Fermi Surfaces under Zeeman Field