Absence of orbital-dependent Mott transition in Ca 2 − x Sr x RuO 4

The Mott transition between the metallic and insulating paramagnetic phases of the layer perovskite Ca 2 − x Sr x RuO 4 is analyzed within the Dynamical Mean Field Theory. To simulate the band narrowing caused by finite Ca doping concentrations, quasi-particle spectra appropriate for Sr 2 RuO 4 are evaluated for increasing values of the on-site Coulomb energy U . At small U the planar geometry splits the t 2 g bands near E F into a wide, two-dimensional d xy band and two narrow, nearly one-dimensional d xz , yz bands. At larger U , however, the spectral distribution of these states exhibits similar correlation features, suggesting a common metal-insulator transition for all t 2 g bands at the same critical U .