Anomalous proximity effects at the interface of s and s+- superconductors

Abstract

We study proximity effects close to a boundary between s and s+- superconductors. Frustration, caused by interaction of the s-wave gap parameter with the opposite-sign gaps of s+- superconductor, leads to several anomalous features. In the case of strong frustration a nontrivial time-reversal-symmetry breaking (TRSB) state, with nonzero phase angles between all gap parameters, is possible. In a more typical state, the s-wave order parameter is aligned with one of the s+- gaps. The other (anti-aligned) gap induces negative feature in the s-wave density of states, which can serve as a fingerprint of s+- state. Another consequence of the frustration is an extended region in the parameter space in which s-wave superconductivity is suppressed, despite being in contact with nominally stronger superconductor. This negative proximity effect is always present for the TRSB state, but extends even into the aligned states. We study these effects within a simple microscopic model assuming dirty limit in all bands, which allows us to model the system in terms of minimum number of the most relevant parameters. The described anomalous features provide a route to establishing the possible s+- state in the iron-based superconductors

arXiv comment19 pages, 11 figures, expanded Introduction, 9 new references

References in corpus (66)

• Unconventional sign-reversing superconductivity in LaFeAsO_(1-x)F_x
• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• High-temperature superconductivity in iron-based materials
• Gap symmetry and structure of Fe-based superconductors
• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
• Magnetism, superconductivity, and pairing symmetry in Fe-based superconductors
• Resonant Spin Excitation in the High Temperature Superconductor Ba0.6K0.4Fe2As2
• Funtional Renormalization Group Study of the Pairing Symmetry and Pairing Mechanism of the FeAs Based High Temperature Superconductors
• A Numerical Renormalization Group Study of the Superconducting and Spin Density Wave Instabilities in MFeAsO${}_{1-x}$F${}_x$ Compounds
• Pairing Symmetry in a Two-Orbital Exchange Coupling Model of Oxypnictides
• Fermi surface nesting induced strong pairing in iron-based superconductors
• Magnetism in Fe-based superconductors
• Quantum criticality and nodal superconductivity in the FeAs-based superconductor KFe2As2
• Competing order and nature of the pairing state in the iron pnictides
• Three-band superconductivity and the order parameter that breaks time-reversal symmetry
• Line nodes in the energy gap of high-temperature superconducting BaFe_2(As_{1-x}P_x)_2 from penetration depth and thermal conductivity measurements
• Unconventional pairing in the iron arsenide superconductors
• Evidence for nodal superconductivity in LaFePO
• Superconducting gap symmetry of Ba0.6K0.4Fe2As2 studied by angle-resolved photoemission spectroscopy
• Evolution of the Fermi surface of BaFe_2(As_{1-x}P_x)_2 on entering the superconducting dome
• London Penetration Depth in Iron - based Superconductors
• Evidence for superconducting gap nodes in the zone-centered hole bands of KFe2As2 from magnetic penetration-depth measurements
• Nodal superconducting gap structure in ferropnictide superconductor BaFe2(As0.7P0.3)2
• Low temperature specific heat of the hole-doped Ba_{0.6}K_{0.4}Fe_2As_2 single crystals and electron-doped SmFeAsO_{0.9}F_{0.1} samples
• Fully Gapped Superconducting State Based on a High Normal State Quasiparticle Density of States in Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$ Single Crystals
• Nodes in the gap structure of the iron-arsenide superconductor Ba(Fe_{1-x}Co_x)_2As_2 from c-axis heat transport measurements
• Superconductivity and spin-density-waves in multi-band metals
• Atomic coexistence of superconductivity and incommensurate magnetic order in the Ba(Fe1-xCox)2As2 pnictide
• Doping dependence of heat transport in the iron-arsenide superconductor Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$: from isotropic to strongly $k$-dependent gap structure
• Disorder induced transition between s_+- and s_++ states in two-band superconductors
• Momentum-dependence of Superconducting Gap, strong-coupling dispersion Kink, and tightly bound Cooper pairs in the high-Tc (Sr,Ba)1-x(K,Na)xFe2As2 superconductors
• Tightly-bound Cooper pair, quasiparticle kinks and clues on the pairing potential in a high Tc FeAs Superconductor
• Doping evolution of superconducting gaps and electronic densities of states in Ba(Fe1-xCox)2As2 iron pnictides
• Superfluid density and penetration depth in Fe-pnictides
• Valley density-wave and multiband superconductivity in Fe-pnictides
• Hole and Electron Contributions to the Transport Properties of Ba(Fe_(1-x)Ru_x)_2As_2 Single Crystals
• Broken time-reversal symmetry in Josephson junction involving two-band superconductors
• Nodeless vs nodal order parameters in LiFeAs and LiFeP superconductors
• Renormalization group flow, competing phases, and the structure of superconducting gap in multi-band models of Iron based superconductors
• Local measurement of the superfluid density in the pnictide superconductor Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ across the superconducting dome
• Optical properties of the iron-arsenic superconductor BaFe1.85Co0.15As2
• The superconducting gaps in LiFeAs: Joint study of specific heat and ARPES
• Theory of heterotic SIS Josephson junctions between single- and multi-gap superconductors
• A doping dependent specific heat study of the superconducting gap in Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Possible phase-sensitive tests of pairing symmetry in pnictide superconductors
• Superconducting Gap Structure of LaFePO Studied by Thermal Conductivity
• Three-dimensional nodal superconducting gap in single crystals Ba(Fe${}_{1-x}$Ni${}_x$)${}_2$As${}_2$
• Calorimetric Evidence of Strong-Coupling Multiband Superconductivity in Fe(Te0.57Se0.43) Single Crystal
• Anisotropic pairing in the iron pnictides
• A generalized proximity effect model in superconducting bi- and tri-layer films
• Experimental Detection of Sign-Reversal Pairing in Iron-Based Superconductors
• Josephson effect between a two-band superconductor with the s++ or s+- pairing symmetry and a conventional s-wave superconductor
• Evidence for multiple gaps in specific heat of LiFeAs crystals
• The proximity effect in normal metal - multiband superconductor hybrid structures
• Isotropic three-dimensional gap in the iron-arsenide superconductor LiFeAs from directional heat transport measurements
• Possible Sign-Reversing s-Wave Superconductivity in Co-Doped BaFe2As2 Proved by Thermal Transport Measurements
• Metastable $\pi$-junction between an s${}_{\pm }$-wave and an s-wave superconductor
• Shapiro Steps as a Direct Probe of $\pm s$-wave Symmetry in Multi-gap Superconducting Josephson Junctions
• Time-reversal symmetry breaking state near the surface of $s_{\pm }$-superconductor
• The current-phase relation in Josephson tunnel junctions
• Statistics of subgap states in $s_{\pm }$ superconductors
• Calorimetric Evidence for Nodes in the Overdoped Ba(Fe${}_{0.9}$Co${}_{0.1}$)${}_2$As${}_2$
• Comment on "Quantum Criticality and Nodal Superconductivity in the FeAs-Based Superconductor KFe${}_2$As${}_2$"
• Proximity fingerprint of s+- superconductivity
• Proximity Effect in Normal Metal - High Tc Superconductor Contacts
• Macroscopic quantum tunneling in multigap superconducting Josephson junctions: Escape rate enhancement via quantum fluctuations of Josephson-Leggett mode

Cited by in corpus (18)

• Impurities in multiband superconductors
• Ground state, collective mode, phase soliton and vortex in multiband superconductors
• Unexpected impact of magnetic disorder on multiband superconductivity
• Proximity and Josephson effects in microstructures based on multiband superconductors
• Cross-band versus intra-band pairing in superconductors: signatures and consequences of the interplay
• Phase diagram of Josephson junction between s and s+- superconductors in dirty limit
• Josephson current and density of states in proximity circuits with s+- superconductors
• Realization of the $\pi$-state in junctions formed by multi-band superconductors with a spin-density-wave
• Quantum Waveguide Theory of the Josephson effect in Multiband Superconductors
• Time-reversal symmetry breaking state in dirty three-band superconductor
• The microscopic basis for phase-sensitive experiments for determination of the order parameter symmetry in Fe-based superconductors
• Atomic-scale Frustrated Josephson Coupling and Multi-condensate Visualization in FeSe
• Quasiclassical circuit-theory of contiguous disordered multiband superconductors
• Josephsonic diagnostic of competing orders in quantum critical multiband superconductors
• Effects of order parameter self-consistency in a $s_{\pm }$-s junction
• Unusual boundary effect on coherency of two-band superconductivity
• Impurity-induced smearing of the spin resonance peak in Fe-based superconductors
• Critical point of the transition between $s_{\pm }$ and $s_{++}$ states of a two-band superconductor with nonmagnetic impurities