  Numerical study of momentum-dependent gap function is presented to make clear
the origin of superconductivity in copper oxides. We claim that antinodal
region with pronounced nesting feature of the Fermi contour gives rise to
superconducting pairing with large momentum under screened Coulomb repulsion.
Such a pairing results in both spatial checkerboard pattern of the
superconducting state below Tc and a gapped state of incoherent pairs in a
broad temperature range above Tc. We explain the momentum dependence of the
coherent spectral weight detected in angle-resolved photoemission spectroscopy
and predict antinodal Bogoliubov quasiparticle interference other than observed
in the nodal region.
