Going beyond the Chandrasekhar-Clogston limit in a flat-band superconductor
arXiv:2109.13245 · doi:10.1103/PhysRevB.105.L060501
Abstract
The Chandrasekhar-Clogston limit normally places stringent conditions on the magnitude of the magnetic field that can coexist with spin-singlet superconductivity, restricting the critical induced Zeeman shift to a fraction of the superconducting gap. Here, we consider a model system where the spin-singlet Cooper pairing in a dispersive band crossing the Fermi level is boosted by an additional flat-band located away from the Fermi level. The boosting of the pairing in the dispersive band allows for nontrivial solutions to the coupled gap equations for spin-splitting fields considerably larger than the superconducting gaps at zero field. Further, the additional Cooper pairing in the flat-band, away from the Fermi level, increases the superconducting condensation energy without affecting the paramagnetic susceptibility of the system, making the free energy favor the superconducting state. This opens up the possibility for spin-singlet superconductivity beyond the standard Chandrasekhar-Clogston limit.
6 pages, 4 figures
References in corpus (9)
- Tunable Phase Boundaries and Ultra-Strong Coupling Superconductivity in Mirror Symmetric Magic-Angle Trilayer Graphene
- A spin triplet supercurrent through the half-metallic ferromagnet CrO2
- Nonlocal Thermoelectric Effects and Nonlocal Onsager Relations in a Three-Terminal Proximity-Coupled Superconductor-Ferromagnet Device
- Chiral Flat Bands: Existence, Engineering and Stability
- In-plane critical magnetic fields in magic-angle twisted trilayer graphene
- Proposal for a phase-coherent thermoelectric transistor
- Desiging Artificial Lieb Lattice on Metal Surface
- Multi-Band Superconductivity and the Steep Band -- Flat Band Scenario
- Stable Sarma State in Two-band Fermi Systems
Cited by in corpus (5)
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- Constrained weak-coupling superconductivity in multiband superconductors
- Exceeding the Chandrasekhar-Clogston limit in flat-band superconductors: A multiband strong-coupling approach
- Flat bands in condensed-matter systems -- perspective for magnetism and superconductivity
- Near-flat-band-driven violation of Pauli limit in heavy fermion superconductors