Superconductivity and spin-density waves: Application to heavy-fermion materials.

摘要: We examine possible superconducting (SC) pairing states competing with the spin-density wave (SDW). On basis of an imperfect-nesting-band model in two dimensions, we investigate a Hamiltonian including on-site repulsive interaction addition to attractive within mean-field approximation. The present theory is applicable unified way both ${T}_{c}$g${T}_{N}$ and ${T}_{c}$${T}_{N}$, where ${T}_{c}$(${T}_{N}$)is transition temperature SC It shown that anisotropic enumerated group theoretically can be categorized into classes: less-competitive competitive according combined symmetry order parameter (parity translational determined by nesting vector). In presence SDW include odd- even-parity are stabilized, but definitely exclude isotropic singlet state. discuss experimental implication our heavy-fermion superconductors ${\mathrm{URu}}_{2}$${\mathrm{Si}}_{2}$, (U,Th)${\mathrm{Be}}_{13}$, (U,Th)${\mathrm{Pt}}_{3}$, U(Pt,Pd${)}_{3}$, which all exhibit Fermi-surface-related instability.