Document Type

Article

Department/Program

Physics

Journal Title

PHYSICAL REVIEW B

Pub Date

2-15-2018

Volume

95

Issue

7

Abstract

We present comprehensive broadband optical spectroscopy data on two insulating phases of vanadium dioxide (VO2): monoclinic M-2 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 M-2 and triclinic phases. Moreover, the optical interband features in the M-2 and triclinic phases are remarkably similar to those observed in the well-studied monoclinic M-1 insulating phase of VO2. As the energy gap is insensitive to the different lattice structures of the three insulating phases, we rule out vanadium-vanadium pairing (the Peierls component) as the dominant contributor to the opening of the gap. Rather, the energy gap arises primarily from intra-atomic Coulomb correlations.

DOI

10.1103/PhysRevB.95.075125

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