Electronic structure and orbital ordering of SrRu$_{1-x}$Ti$_x$O$_3$: GGA+$U$ investigations
Pao-An Lin, Horng-Tay Jeng, and Chen-Shiung Hsue

The electronic structures of Titanium doped Perovskite Ruthenates SrRu$_{1-x}$Ti$_x$O$_3$ with $x$ of 0.25, 0.50, and 0.75 are investigated using the generalized gradient approximation (GGA) as well as the GGA plus Hubbard $U$ (GGA+$U$) scheme. It is found that the Ti substitutions with nearly empty $3d$ orbitals and relatively smaller atomic sizes significantly affect the orbital ordering patterns at Ru sublattices. In addition, the observed metal-insulator transition upon Ti dopant concentration is demonstrated to be driven primarily by the on-site Coulomb correlation $U$. The good agreements between the GGA+$U$ results and the experimental observations reveal that the electron correlation plays an important role in SrRu$_{1-x}$Ti$_x$O$_3$.

© 2008 The American Physical Society.