Eur. Phys. J. B (2018) 91: 225
https://doi.org/10.1140/epjb/e2018-90121-x

Regular Article

The isotropic Compton profile difference across the phase transition of VO₂^★

¹ Department of Physics, University of Helsinki, PO Box 64, FI-00014 Helsinki, Finland
² ESRF – The European Synchrotron, 71 avenue des Martyrs, CS40220, 38043 Grenoble Cedex 9, France

^a e-mail: kari.ruotsalainen@helmholtz-berlin.de

Received: 2 March 2018
Received in final form: 27 June 2018
Published online: 3 October 2018

Abstract

We studied the isotropic Compton profile of the prototypical oxide VO₂ across the temperature induced electronic and structural phase transition at T_C ≈ 340 K. We show that the phase transition leaves an observable signal, which facilitates Compton scattering studies of electronic structure and phase transitions in complex solids in powder form. We compare the experimental results with density functional theory calculations and find agreement in the shape of the difference profile, although the amplitude of the observed features is overestimated. The origin of the disagreement is discussed and we argue that it mainly originates mostly correlation effects beyond our current calculations and possibly to some extent from thermal motion.