Charge transfer at the metal-insulator transition in V$_2$O$_3$ thin films by resonant inelastic x-ray scattering
C. F. Hague, J.-M. Mariot, V. Ilakovac, R. Delaunay, M. Marsi, M. Sacchi, J.-P. Rueff, and W. Felsch

The metal-insulator transition in V$_2$O$_3$ thin films has been studied by resonant inelastic x-ray scattering (RIXS) at the V $L_{3}$ edge. Features belonging to $d$-$d$ excitations, charge transfer between O~$2p$ and V~$3d$ states, and normal x-ray emission-like decay indicate that intra-band, inter-band, and inter-site transitions are involved. In particular our findings are compatible with a more pronounced density of unoccupied non-degenerate $a_{1g}$ states in the paramagnetic insulator (PI) phase compared to the paramagnetic metal (PM) or antiferromagnetic insulator (AFI) phases. The O~$2p$ to V~$3d$ charge transfer is reduced in the PI phase compared to both the PM and AFI phases. The RIXS spectra also provide an estimate of the crystal-field splitting for V$_2$O$_3$.

© 2008 The American Physical Society.