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Zapiski Nauchnykh Seminarov POMI, 1992, Volume 199, Pages 147–176
(Mi znsl5085)
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This article is cited in 1 scientific paper (total in 1 paper)
Superconductive states in the two-dimensional repulsive Hubbard model
C. Malyshev, V. N. Popov
Abstract:
Investigation of the two-dimensional repulsive Hubbard model
is continued for the case when the Fermi level is close to
one of the saddle Van-Hove points of the quasiparticle energy
function. The Bethe–Salpeter equation for the two-particle scattering
amplitude and the system of Dyson–Gor'kov equations for
normal and anomalous Green's functions axe considered. Closeness
of the Van-Hove point and the Fermi level allows to simplify the
investigation. A new method suggested for evaluation the kernel
of investigated equations is suggested.
It is shown, that the nontrivial Cooper pairing (the superposition
of pairings with odd angular momenta) arises if and only
if the Fermi level is close to one of the Van-Hove points. The
superconductive phase transition temperature is maximal for some
special mutual location of the Fermi level and the Van-Hove point.
Two different superconductive solutions (modes) are found which
are antisymmetric functions in the momentum representation. These
two modes coexist in some narrow interval of the doping parameter
around the value of this parameter corresponding to the case of
intersection the Van-Hove point and the Fermi level. Values of
the energy gap are different for these two modes (two different
gap values were observed in some experiments).
Citation:
C. Malyshev, V. N. Popov, “Superconductive states in the two-dimensional repulsive Hubbard model”, Questions of quantum field theory and statistical physics. Part 11, Zap. Nauchn. Sem. POMI, 199, Nauka, St. Petersburg, 1992, 147–176; J. Math. Sci., 77:2 (1995), 3112–3132
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https://www.mathnet.ru/eng/znsl5085 https://www.mathnet.ru/eng/znsl/v199/p147
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Abstract page: | 95 | Full-text PDF : | 48 |
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