  We use a time-dependent dynamical mean-field-hydrodynamic model to study
mixing-demixing in a degenerate fermion-fermion mixture (DFFM). It is
demonstrated that with the increase of interspecies repulsion and/or trapping
frequencies, a mixed state of DFFM could turn into a fully demixed state in
both three-dimensional spherically-symmetric as well as quasi-one-dimensional
configurations. Such a demixed state of a DFFM could be experimentally realized
by varying an external magnetic field near a fermion-fermion Feshbach
resonance, which will result in an increase of interspecies fermion-fermion
repulsion, and/or by increasing the external trap frequencies.
