Electronic Raman scattering in magnetite

Raman spectra of optimally doped magnetite Fe3O4 single crystals reveal broad electronic background extending up to 900 wave numbers 110 meV. Redistribution of this background is observed when sample is cooled below the Verwey transition temperature TV=123 K. In particular, spectra of the low temperature phase show diminished background below 300 wave numbers followed by an enhancement of the electronic background between 300 and 400 wave numbers with subsequent decrease of the background below 400 wave numbers. Such redistribution may be assigned to an opening of the charge gap at about 350±80 wave numbers 43±10 meV. The value of the gap is within the range of recent photoemission data on freshly fractured magnetite sample.