A review of two-band superconductivity: materials and effects on the thermodynamic and reversible mixed-state properties

Abstract

Two-band superconductivity has become an important topic over the last ten years. Extensive experimental and theoretical studies started with MgB2 and are now focused on the iron-based and other new superconductors. In this review, I describe how important thermodynamic, reversible mixed-state, and other superconducting properties are changed by two-band and, for comparison, by other effects such as anisotropy in a single-band material or an energy gap structure different from the conventional s-wave symmetry. The work consists of three main parts, in which I review (i) theoretical models and what they predict for experimentally accessible properties in the two-band and other scenarios, (ii) experimental methods applied for investigating superconducting properties and the results obtained in potential two-band materials, and (iii) materials, for which two- or multi-band superconductivity has been suggested. It is shown that two-band effects appear in most of the analyzed properties and that they can be quite significant but usually fade away as interband interactions increase. Anisotropy often leads to similar modifications in single-band superconductors, which is why the distinction of two-band and anisotropy effects is usually difficult, particularly when the temperature dependence of the quantities is examined. In contrast, the field dependent effects are more often different and thus more often allow a reliable distinction between the models.

40 pages, 14 figures

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Cited by in corpus (47)

• Superconductivity in Few-Layer Stanene
• Imaging superconducting vortex core and lattice with the scanning tunneling microscope
• Two-gap superconductivity in LaNiGa${}_2$ with non-unitary triplet pairing and even parity gap symmetry
• Magnetic field dependence of the density of states in the multiband superconductor $\beta$-Bi${}_2$Pd
• Physical properties of noncentrosymmetric superconductor LaIrSi3: A μSR study
• Superconducting gap structure of FeSe
• Weak Interband-Coupling Superconductivity in the Filled Skutterudite LaPt4Ge12
• Observation of Two Sound Modes in a Binary Superfluid Gas
• Evidence for eight node mixed-symmetry superconductivity in a correlated organic metal
• Ground state, collective mode, phase soliton and vortex in multiband superconductors
• PdTe a 4.5K Type II BCS Superconductor
• Distinct magnetic signatures of fractional vortex configurations in multiband superconductors
• BCS superconductivity near the band edge: Exact results for one and several bands
• Evidence of multiband superconductivity in the $\beta$-phase Mo${}_{1-x}$Re${}_x$ alloys
• Leggett modes and the Anderson-Higgs mechanism in superconductors without inversion symmetry
• Strong electron-phonon coupling and multiband effects in the superconducting $\beta$-phase Mo${}_{1-x}$Re${}_x$ alloys
• Upper critical field as a probe for multiband superconductivity in bulk and interfacial STO
• Multigap Superconductivity in Chiral Noncentrosymmetric TaRh${}_2$B${}_2$
• Superconductivity and the upper critical field in the chiral noncentrosymmetric superconductor NbRh${}_2$B${}_2$
• Mechanism of screening or enhancing the pseudogap throughout the two-band Bardeen-Cooper-Schrieffer to Bose-Einstein condensate crossover
• Classifying induced superconductivity in atomically thin Dirac-cone materials
• Experimental observation of an anomalous peak in isofield M(T) curves in BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$ resembling the fish-tail in $M$($H$) curves further suggesting a possible phase transition in the irreversible regime
• Checkerboard-type patterns of charge stripes in two-gap superconductor ZrB12
• Surface structure and multigap superconductivity of V3Si (111) revealed by scanning tunneling microscopy
• K2Mo3As3 is a Multi-Gap Electron-Phonon Superconductor
• Nodeless superconductivity and the peak effect in the quasi-skutterudites ${\mathrm{Lu}}_3{\mathrm{Os}}_4{\mathrm{Ge}}_{13}$ and ${\mathrm{Y}}_3{\mathrm{Ru}}_4{\mathrm{Ge}}_{13}$
• Insights on unconventional superconductivity in HfV${}_2$Ga${}_4$ and ScV${}_2$Ga${}_4$ from first principles electronic structure calculations
• Evidence of unconventional superconductivity in the Ni-doped NbB2 system
• Elastic anisotropy and thermal properties of extended linear chain compounds MV${}_2$Ga${}_4$ (M = Sc, Zr, Hf) from ab-initio calculations
• Possible multiband superconductivity in the quaternary carbide YRe2SiC
• Inhomogeneous superconductivity in LuxZr1-xB12 dodecaborides with dynamic charge stripes
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• Multiband Semimetallic Electronic Structure of Superconducting Ta2PdSe5
• Critical and Gaussian conductivity fluctuations in BaFe1.9Ni0.1As2 superconductor
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• Quantum Transport Properties of an Exciton Insulator/Superconductor Hybrid Junction
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• Two characteristic contributions to the superconducting state of 2$H$-NbSe${}_2$
• Extended Uniform Ginzburg-Landau Theory for Novel Multiband Superconductors
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• DC-driven separation of fractional flux quanta in two-band superconductors
• Temperature dependence of the lower critical field of the noncentrosymmetric superconductor $\alpha$-BiPd
• Spontaneous Long-range Vortex-antivortex Pair in the Two-band 2D Superconductor
• Specific Heat and the gap structure of a Nematic Superconductor, application to FeSe
• Enhancing long-range order in disordered two-band s-wave superconductors
• First-principles evidence for conventional superconductivity in a quasicrystal approximant