Electronic structure of charge- and spin-controlled Sr1-(x+y)Lax+yTi1- xCrxO3

We present the electronic structure of Sr1-(x+y)Lax+yTi1-xCrxO3 investigated by high-resolution photoemission spectroscopy. In the vicinity of the Fermi level, it was found that the electronic structure was composed of a Cr 3d local state with the t2g3 configuration and a Ti 3d itinerant state. The energy levels of these Cr and Ti 3d states are well interpreted by the difference of the charge-transfer energy of both ions. The spectral weight of the Cr 3d state is completely proportional to the spin concentration x irrespective of the carrier concentration y, indicating that the spin density can be controlled by x as desired. In contrast, the spectral weight of the Ti 3d state is not proportional to y, depending on the amount of Cr doping.