Geometric considerations of the monoclinic–rutile structural transition in VO2
Language
en
Article de revue
This item was published in
Dalton Transactions. 2019-06-25, vol. 48, n° 25, p. 9260-9265
Royal Society of Chemistry
English Abstract
The mechanism of the displacive phase transition in VO2 near the transition temperature is discussed in terms of a geometrical approach, combining simple calculations based on the Brown's band valence model and in situ ...Read more >
The mechanism of the displacive phase transition in VO2 near the transition temperature is discussed in terms of a geometrical approach, combining simple calculations based on the Brown's band valence model and in situ X-ray diffraction experimental results. Considering that the structural origin is well linked to the electrostatic potential optimization as in a Peierls model, our geometrical calculations and experimental studies are in agreement and suggest that VO2 phase transition is the consequence of very short atomic shifts mainly associated to a decrease of the 2nd sphere coulombic interactions. Hence, at a given temperature, the allotropic form (monoclinic versus rutile form) offering the largest unit-cell volume is stabilized over the lower unit-cell volume allotropic, while the transition occurs at the intercept of the unit cell variation versus temperature of the two forms, which exhibit significantly different thermal expansion coefficients.Read less <
Origin
Hal imported