Insulator-to-metal transition in vanadium sesquioxide: does the Mott criterion work in this case?

Abstract

It is shown that the Mott criterion expressed by the simple relation a _B(n _c)^1/3 ≈ 0.25 turns out to be quite successful in describing metal–insulator phase transitions not only in heavily doped semiconductors, but also in transition metal oxides such as VO₂ and V₂O₃. It is found in this article that, in the case of a high-temperature transition ‘paramagnetic insulator – paramagnetic metal’ in vanadium sesquioxide, a _B(n _c)^1/3 = 0.254. Difficulties connected with the analogous description of a low-temperature transition (‘paramagnetic metal – antiferromagnetic insulator’) in V₂O₃ are discussed.

Keywords:

• metal–insulator transition
• Mott criterion
• transition metal oxides
• vanadium sesquioxide

Acknowledgements

This study was supported by the Ministry of Education and Science of Russian Federation, ‘Scientific and Educational Community of Innovation Russia (2009-2113)’ Program through contracts no. 02.740.11.0395, 02.740.11.5179, 14.740.11.0137 and project no. 8051, as well as ‘Development of Scientific Potential of High School (2009-2011)’ Program, project no. 12871. The authors also thank V. P. Novikova for her help in the article preparation.