Photoinduced Reconstruction of Electronic Structure in Half-Metal CrO₂

We investigate the photoinduced effects on the electronic structure for half-metallic ferromagnet CrO₂ (T_c～390K), in which the conducting electrons are totally polarized, by using the LSDA+U method. A significant change is found for the band structure and the density of states (DOS) for CrO₂ under
photo-excitation, especially for the Cr 3dt_2g band: disappearance of the spin-split band, suggesting collapse of the half-metallic state. We ascribe the change of electronic structure under photo-excitation to the wider one-electron band W via the strong hybridization of the down-spin Cr 3d and O 2p
states. Furthermore we discuss the magnetic properties under photo-excitation.