Absence of orbital-dependent Mott transition in Ca2-xSrxRuO4

The Mott transition between the metallic and insulating paramagnetic phases of the layer perovskite Ca2-xSrxRuO4 is analyzed within the Dynamical Mean Field Theory. To simulate the band narrowing caused by finite Ca doping concentrations, quasi-particle spectra appropriate for Sr2RuO4 are evaluated for increasing values of the on-site Coulomb energy U. At small U the planar geometry splits the t(2g) 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(2g) bands at the same critical U.