Soft-x-ray-absorption studies of the electronic-structure changes through theVO2phase transition

Abstract

We present the O 1s and V 2p absorption edges of ${\mathrm{VO}}_{2}$ at room temperature and at T=120 \ifmmode^\circ\else\textdegree\fi{}C, i.e., below and above the metal-insulator transition temperature ${\mathit{T}}_{\mathit{c}}$\ensuremath{\approxeq}67 \ifmmode^\circ\else\textdegree\fi{}C. The O 1s spectra show a clear splitting of 1 eV in the unoccupied ${\mathit{d}}_{\mathrm{?}}$ band below ${\mathit{T}}_{\mathit{c}}$. Because the V 2p absorption edges are dominated by the V 2p-3d interaction in the final state, these spectra show minor changes that cannot be easily correlated with the changes in the unoccupied density of states.