  We investigate the pairing symmetry of the superfluid state in repulsively
interacting three-component (colors) fermionic atoms in optical lattices. When
two of the three color-dependent repulsions are much larger than the other,
pairing symmetry is an extended s wave, although the superfluid state appears
adjacent to the paired Mott insulator in the phase diagram. As the difference
between the three repulsions is decreased in square optical lattices, the
extended s-wave pairing changes into a nodal s-wave pairing and then into a
d-wave pairing. This change in pairing symmetry is attributed to the
competition among the density fluctuations of unpaired atoms, the quantum
fluctuations of the color-density wave, and those of the color-selective
antiferromagnet. This phenomenon can be studied using existing experimental
techniques.We investigate the pairing symmetry of the superfluid state in
repulsively interacting three-component (color) fermionic atoms in optical
lattices. When two of the three color-dependent repulsions are much stronger
than the other, pairing symmetry is an extended $s$ wave although the
superfluid state appears adjacent to the paired Mott insulator in the phase
diagram. On the other hand, when two of the three color-dependent repulsions
are weaker than the other, pairing symmetry is a d_{x^2-y^2}-wave. This change
in pairing symmetry is attributed to the change in the dominant quantum
fluctuations from the density fluctuations of unpaired atoms and the
color-density wave fluctuations to the color-selective antiferromagnet
fluctuations. This phenomenon can be studied using existing experimental
techniques.
