The work by Soares et al. Phys. Rev. B 65, 174506 (2002) investigates the BCS to Bose-Einstein crossover for d-wave pairing in the two-dimensional attractive Hubbard model. Contrary to their claims, we found that a nonpairing region does not exist in the density vs coupling phase diagram. The gap parameter at T=0, as obtained by solving analytically as well as numerically the BCS equations, is in fact finite for any nonzero density and coupling, even in the weak-coupling regime.
Comment on "BCS to Bose-Einstein crossover phase diagram at zero temperature for a d(x2-y2) order parameter superconductor: Dependence on the tight-binding structure"
PERALI, Andrea;PIERI, Pierbiagio;STRINATI CALVANESE, Giancarlo
2003-01-01
Abstract
The work by Soares et al. Phys. Rev. B 65, 174506 (2002) investigates the BCS to Bose-Einstein crossover for d-wave pairing in the two-dimensional attractive Hubbard model. Contrary to their claims, we found that a nonpairing region does not exist in the density vs coupling phase diagram. The gap parameter at T=0, as obtained by solving analytically as well as numerically the BCS equations, is in fact finite for any nonzero density and coupling, even in the weak-coupling regime.File in questo prodotto:
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