Multi-Band Superconductivity and the Steep Band -- Flat Band Scenario

Abstract

The basic features of multi-band superconductivity and its implications are derived. In particular, it is shown that enhancements of the superconducting transition temperature take place due to interband interactions. In addition, isotope effects differ substantially from the typical BCS scheme as soon as polaronic coupling effects are present. Special cases of the model are polaronic coupling in one band as realized e.g., in cuprates, coexistence of a flat band and a steep band like in MgB2, crossovers between extreme cases. The advantages of the multiband approach as compared to the single band BCS model are elucidated and its rather frequent realization in actual systems discussed

16 pages, 9 figures

References in corpus (10)

• Resonant and crossover phenomena in a multiband superconductor tuning the chemical potential near a band edge
• Iron isotope effect on the superconducting transition temperature and the crystal structure of FeSe_1-x
• Absence of an appreciable iron isotope effect on the transition temperature of the optimally doped SmFeAsO_{1-y} superconductor
• Study of temperature dependent atomic correlations in MgB${}_2$
• Ultrafast carrier localisation in the pseudogap state of cuprate superconductors from coherent quench experiments
• Fermi-Bose mixtures and BCS-BEC crossover in high-Tc superconductors
• Electron-phonon coupling and two-band superconductivity of Al- and C-doped MgB2
• Orbital Symmetry and Orbital Excitations in High-$T_c$ Superconductors
• Fe-As bond fluctuations in a double-well potential in LaFeAsO
• Feshbach Shape Resonance for High Tc Pairing in Superlattices of Quantum Stripes and Quantum Wells

Cited by in corpus (5)

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• Room temperature superconductivity dome at a Fano resonance in superlattices of wires
• Going beyond the Chandrasekhar-Clogston limit in a flat-band superconductor
• Lattice Quantum Geometry Controlling 118 K Multigap Superconductivity in Heavily Overdoped CuBa2Ca3Cu4O10+d
• Influence of pressure on properties of multi-gap type-I superconductor BeAu