First Principle Study of the Electronic Structure of Gd<sub>2</sub>SrAl<sub>2</sub>O<sub>7</sub>

Abstract

The ground state electronic structure of Gd2SrAl2O7 are calculated using first principles, we found that only the Density functional theory (DFT) + U can correctly describe the Gd2SrAl2O7 as a charge-transfer type insulator. Gd-O and Al-O bonds have strong covalent character and Sr-O is a perfect ionic bond. The band gap of Gd2SrAl2O7is 3.9 eV, and it is opened due the large U correction for 4f orbit.