We investigate the Mott transitions in two-band Hubbard models with different
bandwidths. Applying dynamical mean field theory, we discuss the stability of
itinerant quasi-particle states in each band. We demonstrate that separate Mott
transitions occur at different Coulomb interaction strengths in general, which
merge to a single transition only under special conditions. This kind of
behavior may be relevant for the physics of the single-layer ruthenates,
Ca2−xSrxRuO4.Comment: 4 pages, 4 figure