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Possible pairing states of the Fe-based superconductors

2008; American Physical Society; Volume: 78; Issue: 13 Linguagem: Inglês

10.1103/physrevb.78.134523

1550-235X

Yunkyu Bang, Han-Yong Choi,

Rare-earth and actinide compounds

We consider the minimal two-band model for the Fe-based superconductors with a phenomenological pairing interaction which mimics short-range antiferromagnetic fluctuations. Two superconducting (SC) gap solutions are found to exist with the model: sign-changing $s$-wave gap ($\ifmmode\pm\else\textpm\fi{}s$ wave) and double $d$-wave gap states. Both solutions hold the approximate relation ${\ensuremath{\Delta}}_{h}^{\text{max}}{N}_{h}\ensuremath{\approx}{\ensuremath{\Delta}}_{e}^{\text{max}}{N}_{e}$, a generic feature of two-band model with a dominant interband pairing interaction. We carried out the calculations of the SC properties of the both SC states such as the density of states, temperature dependencies of spin-lattice relaxation rate $1/{T}_{1}$, Knight shift, and penetration depth, particularly taking into account of the interband coherence factors. The results are discussed in comparison with the currently available experimental data.