Investigation of correlation effects on the electronic structure of 3d1 perovskites

We have investigated the electronic structure of the 3d1 perovskites SrVO3, CaVO3, and YTiO3 by performing ab initio full-potential linearized augmented plane wave band-structure calculations within the density functional theory framework. The electronic band structure with the correct ground state for 3d1 perovskites could not be realized with the generalized gradient approximation (GGA). Although the GGA can explain the metallic ground state of SrVO3 and CaVO3, it fails to find the correct ground state of YTiO3, which is a Mott-Hubbard insulator with a band gap of approximately 0.7eV. Our GGA + U approach with systematic variation of both the electron (U) and the exchange (J) correlation energies has helped in understanding the correct electronic structure of these perovskites. We conducted a series of calculations with different Ueff (U − J) in the GGA + U approach to understand the effect of electron correlation on the electronic structure. Our procedure ultimately succeeded in describing the insulating electronic structure and correct ferromagnetic ground state of YTiO3.