Possible Pairing Symmetry of Superconductor Na_xCoO_2yH_2O

Abstract

To discuss a possibility that the superconductivities in Na_xCoO_2yH_2O are induced by the electron correlation, we investigate the possible pairing symmetry based on the single-band Hubbard model whose dispersion of the bare energy band is obtained by using FLAPW-LDA band structure calculation of Na_xCoO_2yH_2O. The superconducting transition temperature is estimated by solving the Eliashberg equation. In this equation, both normal and anomalous self-energies are calculated up to the third-order terms with respect to the Coulomb repulsion. In the case of spin-singlet pairing, the candidate of pairing symmetry (the maximum eigen value λ_max^SS of Eliashberg's equation) belongs to d-wave(E_2 representation of D_6 group). In the case of spin-triplet pairing, the candidate of pairing symmetry (the maximum eigen value λ_max^ST of Eliashberg's equation) belongs to f_{y(y^{2}-3x^{2})}-wave (B_1 representation of D_6 group). It is found that λ_max^SS\simeqλ_max^ST and the transition temperatures of unconventional pairing state are estimated to be low compared with observed temperature within our simple model.

10 pages, 5 figures

References in corpus (1)

• Unconventional Upper- and Lower-Critical Fields and Normal-State Magnetic Susceptibility of the Novel Superconducting Compound $N{a}_{0.35}Co{O}_2\cdot 1.3H_{2}O$

Cited by in corpus (4)

• Ferromagnetic fluctuation and possible triplet superconductivity in Na_xCoO_2*yH_2O: Fluctuation-exchange study of multi-orbital Hubbard model
• Na${}_x$CoO${}_2$ in the x -> 0 Regime: Coupling of Structure and Correlation effects
• s-wave Superconductivity due to Suhl-Kondo Mechanism in Na${}_x$CoO${}_2\cdot y$H${}_2$O: Effect of Coulomb Interaction and Trigonal Distortion
• Multiple odd-parity superconducting phases in bilayer transition metal dichalcogenides