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Fermi surface, pseudogap and superconductivity in the t-J model. A. Ramšak a nd P. Prelovšek. Faculty of Mathematics and Physics ( Univ . of Ljubljana ) J. Stefan Institute, Ljubljana, Slovenia. &. t - J model. t - J Hamiltonian:. Green’s function s :. Spectral function s :.
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Fermi surface, pseudogap and superconductivity in the t-J model A. Ramšak andP. Prelovšek Faculty of Mathematics and Physics (Univ. ofLjubljana) J. Stefan Institute, Ljubljana, Slovenia &
t-J Hamiltonian: Green’s functions: Spectral functions:
doping-dependent hopping equations of motion for
doping-dependent hopping equation of motion for ‘Self Consistent Born Approximation’: ; …..
doping-dependent hopping equation of motion for SCBA decoupling
doping-dependent hopping equation of motion for SCBA dynamical spin susceptibility
SCBA q (0,) (, ) (0,0) (,0)
(0,) (, ) (0,0) (,0)
(0,) (, ) (0,0) (,0)
Fermi surface Exact diag.: large Fermi surface One hole results: small Fermi surface (hole pockets)
SCBA: 1 hole Fermi arcs?
t’> 0 t’< 0
Finite doping P. Prelovšek and A. Ramšak, Phys. Rev. B, 63, 180606(R) (2001)
PG P. Prelovšek and A. Ramšak, Phys. Rev. B, 63, 180606(R) (2001)
A - B C ? D Hole concentration versus chemical potential and the corresponding electron momentum distribution function nk. P. Prelovšek and A. Ramšak (2002).
(, ) (A)ch=0.28 (0, ) (0, ) (, ) (0,0) nk (,0) (0,0) |nk| (,0)
(, ) (B)ch=0.19 (0, ) (0, ) (, ) (0,0) nk (,0) (0,0) |nk| (,0)
(, ) (C)ch=0.11 (0, ) (0, ) (, ) (0,0) nk (,0) (0,0) |nk| (,0)
(, ) (D)ch=0.04 (0, ) (0, ) (, ) (0,0) nk (,0) (0,0) |nk| (,0)
Aproximate analysis (0,) (, ) (0,0) (,0)
(0, ) (0, 0) (, ) (,0)
(0, ) (, ) (0,0) (,0)
(0, ) (, ) (0,0) (,0)
(0, ) (, ) (0,0) (,0)
(0, ) (, ) (0,0) (,0)
QP P. Prelovšek and A. Ramšak(2002).
A(k,) k kF /t
Superconductivity extract Ramšak and Prelovšek, 2003
Summary Fermi surface Pseudogap Superconductivity