Naslov
Superconducting instabilities of the non-half-filled Hubbard model in two dimensions

Autori
Zanchi, Dražen ; Schulz, H. J.

Izvornik
Physical review. B, Condensed matter (0163-1829) 54 (1996), 13; 9509-9519

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
high-temperature superconductors ; fluctuating electron-systems ; T-C superconductors ; conserving approximations ; order-parameter ; gap ; dependence ; symmetry ; state

Sažetak
The problem of weakly correlated electrons on a square lattice is formulated in terms of a one-loop renormalization group. Starting from the action for the entire Brillouin zone we reduce successively the cutoff Lambda about the Fermi surface and follow the renormalization of the coupling U as a function of three energy-momenta. We calculate the intrinsic temperature scale T-co where the renormalization-group flow crosses over from the regime (Lambda > T-co) where the electron-electron (e-e) and electron-hole (e-h) terms are equally important to the regime (Lambda < T-co) where only the e-e term plays a role. In the low-energy regime only the pairing interaction V is marginally relevant, containing contributions from all renormalization-group steps of the regime Lambda > T-co. We identify the most attractive eigenvalue lambda(min) of V-Lambda = Tco. At low filling, lambda(min) corresponds to the B-2 representation (d(xy) symmetry), while near half filling the strongest attraction occurs in the B-1 representation (d(x2-y2) symmetry). In the direction of the van Hove singularities, the order parameter shows peaks with increasing strength as one approaches half filling. We also give a possible interpretation of angle resolved photoemission spectroscopy experiments trying to determine the symmetry of the order parameter in the high-T-c compound Bi2Sr2CaCu2O8.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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