Europhys. Lett.
Volume 69, Number 6, March 2005
Page(s) 984 - 989
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 16 February 2005
Europhys. Lett., 69 (6), pp. 984-989 (2005)
DOI: 10.1209/epl/i2004-10430-0

$\chem{VO_2}$: A two-fluid incoherent metal?

M. S. Laad1, L. Craco2 and E. Müller-Hartmann2

1  Department of Physics, Loughborough University - Loughborough, LE11 3TU, UK
2  Institut für Theoretische Physik, Universität zu Köln 77 Zülpicher Strasse, D-50937 Köln, Germany

received 3 September 2004; accepted in final form 14 January 2005
published online 16 February 2005

We present ab initio LDA+DMFT results for the many-particle density of states of $\chem{VO_2}$ on the metallic side of the strongly first-order (T-driven) insulator-metal transition. In strong contrast to LDA predictions, there is no remnant of even correlated Fermi-liquid behavior in the correlated metal. Excellent quantitative agreement with published photoemission and X-ray absorption experiments is found in the metallic phase. We argue that the absence of FL-quasiparticles provides a natural explanation for the bad-metallic transport for T>340$\un{K}$. Based on this agreement, we propose that the I-M transition in $\chem{VO_2}$ is an orbital-selective Mott transition, and point out the relevance of orbital-resolved one-electron and optical spectroscopy to resolve this outstanding issue.

71.28.+d - Narrow-band systems; intermediate-valence solids.
71.30.+h - Metal-insulator transitions and other electronic transitions.
72.10.-d - Theory of electronic transport; scattering mechanisms.

© EDP Sciences 2005