Condensed Matter Physics, 1996, No. 7, p. 139-148, English
DOI:10.5488/CMP.7.139
Title: SUPERCONDUCTING PAIRING OF SPIN POLARONS IN THE t-J MODEL
Authors: N.M.Plakida (Joint Institute for Nuclear Research, 141980 Dubna, Russia),
P.Horsch, A.Liechtenstein (Max-Planck-Institute fuer Festkoerperforschung,
Stuttgart, Germany),
V.S.Oudovenko (Joint Institute for Nuclear Research, 141980 Dubna, Russia)
A quasiparticle spectrum of doped holes
and their superconducting pairing in the CuO2 plane is studied within
a spin polaron t-J model on a two-sublattice antiferromagnet.
A self-consistent system of equations for hole and
magnon matrix Green functions in the noncrossing approximation
is solved numerically by the fast Fourier
transformation method. We obtain a strong renormalization of the hole
spectrum due to spin fluctuations that result in formation of
spin polarons described by the coherent part of the spectrum.
We also observe a singlet d-wave superconducting pairing
for two spin polarons on different sublattices,
mediated by spin-fluctuation exchange.
A maximal superconducting temperature Tc ~ 0.01t is obtained
around the hole concentration 0.25 for t=0.4J.
We argue that the superconducting
pairing of spin polarons for the t-J model with strong electron
correlations represents the mechanism of high-temperature
superconductivity.
Comments: Refs. 26, Figs. 5, Tabs. 0.