Electronic entropy contribution to the metal insulator transition in VO2

Abstract

VO₂ experiences a metal-insulator transition at 340 K. Discontinuities in electronic transport properties, such as the Seebeck coefficient and the electronic conductivity, suggest that there is a significant change in the electronic structure upon metallization. However, the thermodynamic nature of this transformation remains difficult to describe using conventional computational and experimental methods. This has led to disagreement over the relative importance of the change in electronic entropy with respect to the overall transition entropy. A method is presented that links measurable electronic transport properties to the change in electronic state entropy of conduction electrons. The change in electronic entropy is calculated to be 9.2±0.7 J/mol K which accounts for 62%-67% of the total transition entropy. This compares favorably with some estimates of the vibrational entropy.