  The existence and the properties of self-bound quark matter in the NJL model
at zero temperature are investigated in mean-field approximation, focusing on
inhomogeneous structures with one-dimensional spatial modulations. It is found
that the most stable homogeneous solutions which have previously been
interpreted as schematic quark droplets are unstable against formation of a
one-dimensional soliton-antisoliton lattice. The solitons repel each other, so
that the minimal energy per quark is realized in the single-soliton limit. The
properties of the solitons and their interactions are discussed in detail, and
the effect of vector interactions is estimated. The results may be relevant for
the dynamics of expanding quark matter.
