Electronic structure of YMn2O5 studied by EELS and first-principles calculations

The electronic structure of multiferroic YMn2O5 material has been studied by use of the generalized gradient approximation （GGA）. The results demonstrate that the oxygen 2p and manganese 3d orbitals are strongly hybridized. Considering the on-site Coulomb interaction U, we performed the GGA＋U calculations for 0 〈 U ≤8 eV, and it is found that the increase of U could enlarge the band gap and, on the other hand, weaken the Mn-O hybridization. The experimental measurements of the electron energy-loss spectrometry （EELS） exhibit a rich variety of structural features in both O-K edge and Mn-L edges. A theoretical and experimental analysis on the O-K edge suggests that the on-site Coulomb interaction （U） in YMn2O5 could be less than 4 eV. Certain electronic structural features of LaMn2O5 have been discussed in comparison with those of YMn2O5.