  Multiband superconductors support the excitation of vortices with fractional
quantum flux, known as fractional vortices. In the ground state, the fractional
vortices in different bands bond together to form a composite vortex with the
standard flux quantum $\Phi_0$; thus, it is difficult to stabilize the
fractional vortices. Here we show that fractional vortex lattices can be
stabilized in multiband superconductors with a periodic pinning array at the
half matching field of the composite system, when full matching of the
fractionalized vortices occurs. In the presence of a high current, the
fractional vortices in different bands decouple and move at different
velocities. When the current is turned off suddenly, the fractional vortices in
different bands may be trapped at different pinning sites. This system also
exhibits rich dynamic behavior, and for fractional vortices in two-band
superconductors we find a phases where the vortices one band are pinned and the
vortices in the other band are moving. These different phases can be observed
in transport measurements, and produce a new type of self-induced Shapiro steps
that can arise under the application of only a dc drive.
