  We present results from a theoretical and experimental study of
spin-splitting in small open lateral quantum dots (i.e. in the regime when the
dot is connected to the reservoirs via leads that support one or more
propagating modes). We demonstrate that the magnetoconductance shows a
pronounced splitting of the conductance peaks (or dips) which persists over a
wide range of magnetic fields (from zero field to the edge-state regime) and is
virtually independent of magnetic field. A numerical analysis of the
conductance and the dot eigenspectrum indicates that this feature is related to
a lifting of the spin degeneracy in the corresponding closed dot associated
with the interaction between electrons of opposite spin.
