$\chem{V\tx{-}V}$ bond length fluctuations in $\chem{VO}$ $_x$

J. B. Goodenough; F. Rivadulla; E. Winkler; J.-S. Zhou

doi:doi:10.1209/epl/i2003-00161-8

DOI: 10.1209/epl/i2003-00161-8
Europhys. Lett., 61 (4) , pp. 527-533 (2003)

$\chem{V\tx{-}V}$ bond length fluctuations in $\chem{VO}$ _x

J. B. Goodenough, F. Rivadulla, E. Winkler and J.-S. Zhou

Texas Materials Institute, ME/MS & E, ETC 9.102, The University of Texas at Austin 1 University Station, C2201, Austin, TX 78712, USA

(Received 29 August 2002; accepted in final form 4 December 2002)

Abstract
We report a significantly stronger suppression of the phonon contribution to the thermal conductivity in $\chem{VO}$ _x than can be accounted for by disorder of the 16% atomic vacancies present in $\chem{VO}$ . Since the transition from localized to itinerant electronic behavior is first order and has been shown to be characterized by bond length fluctuations in several transition-metal oxides with the perovskite structure, we propose that cooperative $\chem{V\tx{-}V}$ bond length fluctuations play a role in $\chem{VO}$ similar to the $\chem{M\tx{-}O}$ bond length fluctuations in the perovskites. This model is able to account for the strong suppression of the thermal conductivity, the existence of a pseudogap confirmed by thermoelectric power, an anomalously large Debye-Waller factor, the temperature dependence of the magnetic susceptibility, and the inability to order atomic vacancies in $\chem{VO}$ .

PACS
74.25.Fy - Transport properties (electric and thermal conductivity, thermoelectric effects, etc.).
71.27.+a - Strongly correlated electron systems; heavy fermions.
72.15.-v - Electronic conduction in metals and alloys.

© EDP Sciences 2003

bond length fluctuations in x

$\chem{V\tx{-}V}$ bond length fluctuations in $\chem{VO}$ _x