Electronic Structure of Charge- and Spin-controlled Sr_{1-(x+y)}La_{x+y}Ti_{1-x}Cr_{x}O_{3}

摘要

We present the electronic structure ofSr_{1-(x+y)}La_{x+y}Ti_{1-x}Cr_{x}O_{3} investigated by high-resolutionphotoemission spectroscopy. In the vicinity of Fermi level, it was found thatthe electronic structure were composed of a Cr 3d local state with thet_{2g}^{3} configuration and a Ti 3d itinerant state. The energy levels ofthese Cr and Ti 3d states are well interpreted by the difference of thecharge-transfer energy of both ions. The spectral weight of the Cr 3d state iscompletely proportional to the spin concentration x irrespective of the carrierconcentration y, indicating that the spin density can be controlled by x asdesired. In contrast, the spectral weight of the Ti 3d state is notproportional to y, depending on the amount of Cr doping.