Magnetic field dependence of the metal-insulator 'Mott transition': a study of the compound VO2

Abstract

A theory of the metal-insulator transition, taking into account the effects of an external magnetic field is presented. Comparison with experimental susceptibility and optical data for VO2 is good and yields for theoretical parameters the values: Intra-atomic Coulomb integral I approximately=0.7 eV; density of states N(Ef) approximately=1023 cm-3 eV-1 ratio IN(Ef)/N approximately=10; optical energy gap Eg approximately=0.7 eV. The insulating phase stability criterion is shown to be identical with Mott's. The existence of a critical field Hc such that higher magnetic fields destroy the insulating phase is derived.