Multiband strong-coupling superconductors with spontaneously broken time-reversal symmetry

Abstract

We study superconducting three-band systems within strong-coupling Eliashberg theory. In particular, we search for phase-frustrated superconducting systems with spontaneous time-reversal symmetry breaking (TRSB) states. The emergence of TRSB states in multiband systems has so far been studied using microscopic weak-coupling BCS theory or more phenomenological effective field theories such as multi-component Ginzburg-Landau theories. For systems with three disjoint Fermi surfaces whose electrons experience interactions mediated by phonons, we present a microscopic analysis showing that TRSB states also exist within a strong-coupling microscopic theory. The systems we consider have sizable electron-phonon couplings, putting them into the strong-coupling regime. They are thus a fitting description for strong-coupling materials such as some of the iron pnictides. Moreover, as the TRSB states are challenging to find numerically, we calculate the free energy of multiband systems within strong-coupling theory and make explicit use of it to pin down the TRSB states' elusive nature. Since Eliashberg theory is well incorporated with first-principles calculations, our strong-coupling approach might help facilitate a more efficient search for candidate materials that can exhibit TRSB.

15 pages, 6 figures

References in corpus (24)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• Superconductivity and Phase Diagram in the Iron-based Arsenic-oxides ReFeAsO1-delta (Re = rare earth metal) without F-Doping
• Ironing out the details of unconventional superconductivity
• Ginzburg-Landau theory of vortices in a multi-gap superconductor
• Superconducting gap symmetry of Ba0.6K0.4Fe2As2 studied by angle-resolved photoemission spectroscopy
• Possible Topological Superconducting Phases of MoS${}_2$
• Momentum dependence and nodes of the superconducting gap in iron-pnictides
• Chiral CP^2 skyrmions in three-band superconductors
• Ginzburg-Landau theory for multiband superconductors: microscopic derivation
• Emergent phenomena in multicomponent superconductivity: an introduction to the focus issue
• Superconducting Properties of the $s^{\pm }$-wave state: Fe-based superconductors
• Acoustic-phonon-mediated superconductivity in moiréless graphene multilayers
• Distinguishing between $s+id$ and $s+is$ pairing symmetries in multiband superconductors through spontaneous magnetization pattern induced by a defect
• Breakdown of the Migdal-Eliashberg theory and a theory of lattice-fermionic superfluidity
• Heat capacity double transitions in time-reversal symmetry broken superconductors
• Penetration depth, lower critical fields, and quasiparticle conductivity in Fe-arsenide superconductors
• Superconductivity near a quantum critical point in the extreme retardation regime
• Demonstration of $\mathbb{C}{P}^2$ skyrmions in three-band superconductors by self-consistent solutions to a Bogoliubov-de Gennes model
• Superconductivity out of a non-Fermi liquid. Free energy analysis
• Constrained weak-coupling superconductivity in multiband superconductors
• Exceeding the Chandrasekhar-Clogston limit in flat-band superconductors: A multiband strong-coupling approach
• Current-loops, phase transitions, and the Higgs mechanism in Josephson-coupled multi-component superconductors
• Strong electron-boson coupling in the iron-based superconductor BaFe1.9Pt0.1As2 revealed by infrared spectroscopy

Cited by in corpus (5)

• Field-free Josephson diode effect in interacting chiral quantum dot junctions
• Phonon-mediated intrinsic topological superconductivity in Fermi arcs
• Exceeding the Chandrasekhar-Clogston limit in flat-band superconductors: A multiband strong-coupling approach
• Strong-coupling approach to temperature dependence of competing orders of superconductivity: Possible time-reversal symmetry breaking and nontrivial topology
• Mechanism for Nodal Topological Superconductivity on PtBi${}_2$ Surface