Leggett mode in a strong-coupling model of iron arsenide superconductors

Abstract

Using a two-orbital model of the superconducting phase of the pnictides, we compute the spectrum of the Leggett mode -- a collective excitation of the phase of the superconducting gap known to exist in multi-gap superconductors -- for different possible symmetries of the superconducting order parameter. Specifically, we identify the small regions of parameter space where the Leggett mode lies below the two-particle continuum, and hence should be visible as a sharp resonance peak. We discuss the possible utility of the Leggett mode in distinguishing different momentum dependencies of the superconducting gap. We argue that the observation of a sharp Leggett mode would be consistent with the presence of strong electron-electron correlations in iron-based superconductors. We also emphasize the importance of the orbital character of the Leggett mode, which can result in an experimental observation of the mode in channels other than $A_{1g}$.

References in corpus (30)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Superconductivity at 43 K in Samarium-arsenide Oxides $SmFeAs{O}_{1-x}{F}_x$
• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• Superconductivity at 41 K and its competition with spin-density-wave instability in layered CeO${}_{1-x}$F${}_x$FeAs
• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
• Superconductivity up to 37 K in (A1-xSrx)Fe2As2 with A=K and Cs
• Magnetism, superconductivity, and pairing symmetry in Fe-based superconductors
• Strong Correlations and Magnetic Frustration in the High Tc Iron Pnictides
• Superconductivity at 25 K in hole doped $(L{a}_{1-x}S{r}_x)OFeAs$
• Origin of the ~150 K Anomaly in LaOFeAs; Competing Antiferromagnetic Superexchange Interactions, Frustration, and Structural Phase Transition
• A minimal two-band model for the superconducting Fe-pnictides
• Superconductivity at 52 K in iron-based F-doped layered quaternary compound Pr[O1-xFx]FeAs
• Pairing Symmetry in a Two-Orbital Exchange Coupling Model of Oxypnictides
• Multiband magnetism and superconductivity in Fe-based compounds
• Evolution from Itinerant Antiferromagnet to Unconventional Superconductor with Fluorine Doping in La(O_{1-x}F_{x})FeAs Revealed by ^{75}As and ^{139}La Nuclear Magnetic Resonance
• ${}^{75}$As NMR studies of superconducting LaO${}_{0.9}$F${}_{0.1}$FeAs
• Nodal Spin Density Wave and band topology of the FeAs based materials
• Microwave Penetration Depth and Quasiparticle Conductivity in PrFeAsO_1-y Single Crystals : Evidence for a Full-Gap Superconductor
• Spin-triplet p-wave pairing in a 3-orbital model for iron pnictide superconductors
• NMR relaxation rate in superconducting pnictides: extended $s_{\pm }$ scenario
• Superconducting properties of Fe-based layered superconductor LaO${}_{0.9}$F${}_{0.1-\delta }$FeAs
• Observation of Leggett's collective mode in a multi-band MgB2 superconductor
• 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
• Momentum dependence and nodes of the superconducting gap in iron-pnictides
• Antiferromagnetically Driven Electronic Correlation in Iron Pnictides and Cuprates
• Experimental Consequences of the S-wave $\cos (k_x)\cdot \cos (k_y)$ Superconductivity in the Iron-Pnictides
• Non-exponential London penetration depth in Ba${}_{1-}$K${}_x$Fe${}_2$As${}_2$ single crystals
• Spin Fluctuation Dynamics and Multiband Superconductivity in Iron Pnictides
• Antiferromagnetic Correlation and the Pairing Mechanism of the Cuprates and Iron Pnictides : a View From the Functional Renormalization Group Studies
• Theory of Raman response in a superconductor with extended s-wave symmetry: Application to Fe-pnictides

Cited by in corpus (9)

• Nonlinear optical response of collective modes in multiband superconductors assisted by nonmagnetic impurities
• Ground state, collective mode, phase soliton and vortex in multiband superconductors
• Collective modes in multiband superfluids and superconductors: Multiple dynamical classes
• Distinguishing between $s+id$ and $s+is$ pairing symmetries in multiband superconductors through spontaneous magnetization pattern induced by a defect
• Optical response of the Leggett mode in multiband superconductors in the linear response regime
• Classification of Lifshitz invariant in multiband superconductors: an application to Leggett modes in the linear response regime in Kagome lattice models
• Superconducting Order Parameters in overdoped BaFe${}_{1.86}$Ni${}_{0.14}$As${}_2$ Revealed by Multiple Andreev Reflection Spectroscopy of Planar Break-Junctions
• Optically active Higgs and Leggett modes in multiband pair-density-wave superconductors with Lifshitz invariant
• Direct observation of the spin exciton in Andreev spectroscopy of iron-based superconductors