The magnetisation distribution and band structure in the metallic phase of vanadium dioxide

The magnetisation density associated with the susceptibility of vanadium dioxide in the metallic phase has been measured using the polarised neutron technique. The results have been interpreted as giving the spatial distribution of the conduction electrons. Fourier transformation of the measured magnetic structure factors gives a projection in which the density is well localised on the vanadium sites. The density around the vanadium sites is not spherically symmetrical but shows a small elongation towards the oxygen neighbours in <110> 110 directions. The results have been compared with calculations of the magnetic structure factors corresponding to current models of the band structure of VO2. The comparisons show that to obtain adequate agreement between theory and experiment it must be assumed that there are electrons in all three sub-bands of the Tsub(2g) manifold. (author)