Dielectric Spectroscopy of Strongly Correlated Electronic States of Vanadium Dioxide


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The thermal evolution of the conductivity of a VO2 film and database-obtained band gap Eg of film nanocrystallites is traced in the temperature range of –196°C < T < 100°C (77 K < T < 273 K); the level position of donor impurity centers is determined to be Ed = 0.04 eV. It is shown that energy Eg decreases from 0.8 to ∼0 eV with an increase in temperature in the range of 273 K < T < 300 K, which is caused by the narrowing of the energy gap due to correlation effects and considered as the temperature-extended Mott “insulator–metal” electron phase transition with the monoclinic lattice symmetry retained. The subsequent jump in the symmetry from monoclinic to tetragonal with a further increase in temperature is considered as the Peierls structural phase transition, the temperature of which is in the vicinity of 340 K and determined by the size effects, nonstoichiometry of VO2 film nanocrystallites, and degree of their adhesion to the substrate.

Sobre autores

A. Il’inskii

Ioffe Institute

Autor responsável pela correspondência
Email: ilinskiy@mail.ioffe.ru
Rússia, St. Petersburg, 194021

R. Kastro

Herzen State Pedagogical University

Email: ilinskiy@mail.ioffe.ru
Rússia, St. Petersburg, 191186

E. Nikulin

Ioffe Institute

Email: ilinskiy@mail.ioffe.ru
Rússia, St. Petersburg, 194021

E. Shadrin

Ioffe Institute

Email: ilinskiy@mail.ioffe.ru
Rússia, St. Petersburg, 194021

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