Quasiparticle bands of the two-dimensional Hubbard model are calculated
using the Roth two-pole approximation to the one-particle Green’s
function. Excellent agreement is obtained with recent Monte Carlo
calculations, including an anomalous volume of the Fermi surface
near half-filling, which can possibly be explained in terms of a
breakdown of Fermi liquid theory. The calculated bands are very flat
around the (π,0) points of the Brillouin zone in agreement with photoemission
measurements of cuprate superconductors. With doping there is a shift
in spectral weight from the upper band to the lower band. The Roth
method is extended to deal with superconductivity within a four-pole
approximation allowing electron-hole mixing. It is shown that triplet
p-wave pairing never occurs. A self-consistent solution with singlet
dx2-y2-wave pairing is found and optimal doping occurs when the van
Hove singularity, corresponding to the flat band part, lies at the
Fermi level. Nearest-neighbor antiferromagnetic correlations play
an important role in flattening the bands near the Fermi level and
in favoring superconductivity. However, the mechanism for superconductivity
is a local one, in contrast to spin-fluctuation exchange models.
For reasonable values of the hopping parameter the transition temperature
Tc is in the range 10–100 K. The optimum doping δc lies between 0.14
and 0.25, depending on the ratio U/t. The gap equation has a BCS-like
form and 2Δmax/kTc≃4.
%0 Journal Article
%1 Beenen1995
%A Beenen, J.
%A Edwards, D. M.
%D 1995
%I American Physical Society
%J Phys. Rev. B
%K imported
%N 18
%P 13636--13651
%R 10.1103/PhysRevB.52.13636
%T Superconductivity in the two-dimensional Hubbard model
%V 52
%X Quasiparticle bands of the two-dimensional Hubbard model are calculated
using the Roth two-pole approximation to the one-particle Green’s
function. Excellent agreement is obtained with recent Monte Carlo
calculations, including an anomalous volume of the Fermi surface
near half-filling, which can possibly be explained in terms of a
breakdown of Fermi liquid theory. The calculated bands are very flat
around the (π,0) points of the Brillouin zone in agreement with photoemission
measurements of cuprate superconductors. With doping there is a shift
in spectral weight from the upper band to the lower band. The Roth
method is extended to deal with superconductivity within a four-pole
approximation allowing electron-hole mixing. It is shown that triplet
p-wave pairing never occurs. A self-consistent solution with singlet
dx2-y2-wave pairing is found and optimal doping occurs when the van
Hove singularity, corresponding to the flat band part, lies at the
Fermi level. Nearest-neighbor antiferromagnetic correlations play
an important role in flattening the bands near the Fermi level and
in favoring superconductivity. However, the mechanism for superconductivity
is a local one, in contrast to spin-fluctuation exchange models.
For reasonable values of the hopping parameter the transition temperature
Tc is in the range 10–100 K. The optimum doping δc lies between 0.14
and 0.25, depending on the ratio U/t. The gap equation has a BCS-like
form and 2Δmax/kTc≃4.
@article{Beenen1995,
abstract = {Quasiparticle bands of the two-dimensional Hubbard model are calculated
using the Roth two-pole approximation to the one-particle Green’s
function. Excellent agreement is obtained with recent Monte Carlo
calculations, including an anomalous volume of the Fermi surface
near half-filling, which can possibly be explained in terms of a
breakdown of Fermi liquid theory. The calculated bands are very flat
around the (π,0) points of the Brillouin zone in agreement with photoemission
measurements of cuprate superconductors. With doping there is a shift
in spectral weight from the upper band to the lower band. The Roth
method is extended to deal with superconductivity within a four-pole
approximation allowing electron-hole mixing. It is shown that triplet
p-wave pairing never occurs. A self-consistent solution with singlet
dx2-y2-wave pairing is found and optimal doping occurs when the van
Hove singularity, corresponding to the flat band part, lies at the
Fermi level. Nearest-neighbor antiferromagnetic correlations play
an important role in flattening the bands near the Fermi level and
in favoring superconductivity. However, the mechanism for superconductivity
is a local one, in contrast to spin-fluctuation exchange models.
For reasonable values of the hopping parameter the transition temperature
Tc is in the range 10–100 K. The optimum doping δc lies between 0.14
and 0.25, depending on the ratio U/t. The gap equation has a BCS-like
form and 2Δmax/kTc≃4.},
added-at = {2010-11-06T00:14:39.000+0100},
author = {Beenen, J. and Edwards, D. M.},
biburl = {https://www.bibsonomy.org/bibtex/2b5e01c2f04c70c98fdad2fa31d4e4e4e/nplumb},
doi = {10.1103/PhysRevB.52.13636},
file = {:C\:\\Users\\Nick\\Documents\\Papers\\Beenen & Edwards - Superconductivity in the two-dimensional Hubbard model.pdf:PDF},
interhash = {4b347b05572700b6af9a6c299d500a10},
intrahash = {b5e01c2f04c70c98fdad2fa31d4e4e4e},
journal = {Phys. Rev. B},
keywords = {imported},
month = Nov,
number = 18,
numpages = {15},
owner = {Nick},
pages = {13636--13651},
publisher = {American Physical Society},
timestamp = {2010-11-06T00:14:40.000+0100},
title = {Superconductivity in the two-dimensional Hubbard model},
volume = 52,
year = 1995
}