Non-Fermi-Liquid Transport Phenomena and Superconductivity Driven by Orbital Fluctuations in Iron Pnictides: Analysis by Fluctuation-Exchange Approximation

Abstract

We study the five-orbital Hubbard model including the charge quadrupole interaction for iron pnictides. Using the fluctuation-exchange (FLEX) approximation, orbital fluctuations evolve inversely proportional to the temperature, and therefore the resistivity shows linear or convex T-dependence for wide range of temperatures. We also analyze the Eliashberg gap equation, and show that s-wave superconducting state without sign reversal (s++ -wave state) emerges when the orbital fluctuations dominate over the spin fluctuations. When both fluctuations are comparable, their competition gives rise to a nodal s-wave state. The present study offers us a unified explanation for both the normal and superconducting states.

6 pages, 5 figures, full paper version of arXiv:1009.3882

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Cited by in corpus (5)

• Self-Consistent Vertex Correction Analysis for Iron-Based Superconductors: Mechanism of Coulomb-Interaction-Driven Orbital Fluctuations
• Unconventional Hall effect in pnictides from interband interactions
• Fermi arcs, pseudogap and collective excitations in doped Sr2IrO4: A generalized fluctuation exchange study
• Effect of inelastic scattering on the nuclear magnetic relaxation rate 1/T1T in iron-based superconductors
• Universal quasi-degenerate orbital origin of two-dome phases in iron pnictide superconductors