  We employ a time-dependent mean-field-hydrodynamic model to study the
generation of bright solitons in a degenerate fermion-fermion mixture in a
cigar-shaped geometry using variational and numerical methods. Due to a strong
Pauli-blocking repulsion among identical spin-polarized fermions at short
distances there cannot be bright solitons for repulsive interspecies
interactions. Employing a linear stability analysis we demonstrate the
formation of stable solitons due to modulational instability of a
constant-amplitude solution of the model equations for a sufficiently
attractive interspecies interaction. We perform a numerical stability analysis
of these solitons and also demonstrate the formation of soliton trains by
jumping the effective interspecies interaction from repulsive to attractive.
These fermionic solitons can be formed and studied in laboratory with present
technology.
