Mean-field approach to unconventional superconductivity

William Sacks (1) , Alain Mauger (1) , Yves Noat (2)

1 IMPMC - Institut de minéralogie, de physique des matériaux et de cosmochimie
2 INSP - Institut des Nanosciences de Paris

We propose a model that connects the quasiparticle spectral function of high-T c superconductors to the condensation energy. Given the evidence for pair correlations above TcTc, we consider a coarse-grain Hamiltonian of fluctuating pairs describing the incoherent pseudogap (PG) state, together with a novel pair-pair interaction term that restores long-range superconducting (SC) coherence below TcTc. A mean-field solution then leads to a self-consistent gap equation containing the new pair-pair coupling. The corresponding spectral function A(k,E)A(k,E) reveals the characteristic peak-dip-hump features of cuprates, now observed on iron pnictides (LiFeAs). The continuous transition from SC to PG states is discussed.

Mots clés: Unconventional superconductivity; Pseudogap; Spectral function; Inhomogeneity

William Sacks, Alain Mauger, Yves Noat. Mean-field approach to unconventional superconductivity. Physica C: Superconductivity, 2014, 503, pp.14-24. ⟨10.1016/j.physc.2014.04.041⟩. ⟨hal-01048674⟩