Electronic Structure of Charge- and Spin-Controlled Sr_(1-(x+y))La_(x+y)Ti_(1-x)Cr_xO_3

摘要

We present the electronic structure of Sr_(1-(x+y))La_(x+y)Ti_(1-x)Cr_xO_3 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 t_(2g)~3 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.