The insulating phases of vanadium dioxide are Mott-Hubbard insulators

Abstract

We present the first comprehensive broadband optical spectroscopy data on two insulating phases of vanadium dioxide (VO2): monoclinic M2 and triclinic. The main result of our work is that the energy gap and the electronic structure are essentially unaltered by the first-order structural phase transition between the M2 and triclinic phases. Moreover, the optical interband features in the M2 and triclinic phases are remarkably similar to those observed in the well-studied monoclinic M1 insulating phase of VO2. As the energy gap is insensitive to the different lattice structures of the three insulating phases, we rule out Peierls effects as the dominant contributor to the opening of the gap. Rather, the energy gap arises from intra-atomic Coulomb correlations.

5 pages, 4 figures

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Cited by in corpus (4)

• Thermal coupling and effect of subharmonic synchronization in a system of two VO2 based oscillators
• Electrical switching and oscillations in vanadium dioxide
• Observation of weakened V-V dimers in the monoclinic metallic phase of strained VO2
• Occupation switching of $d$ orbitals probed via hyperfine interactions in vanadium dioxide