  We study cross-flavor Cooper pairing in a relativistic system of two fermion
species with mismatched Fermi surfaces. We find that there exist gapless phases
which are characterized by either one or two gapless nodes in the energy
spectra of their quasiparticles. An analysis of the current-current correlator
reveals that, at strong coupling, both of these gapless phases can be free of
magnetic instabilities and thus are stable. This is in contrast to the
weak-coupling case where there are always two gapless nodes and the phase
becomes magnetically unstable.
