Abstract
We present comprehensive broadband optical spectroscopy data on two insulating phases of vanadium dioxide : monoclinic 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 and triclinic phases. Moreover, the optical interband features in the and triclinic phases are remarkably similar to those observed in the well-studied monoclinic insulating phase of . 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.
- Received 19 May 2016
- Revised 20 December 2016
DOI:https://doi.org/10.1103/PhysRevB.95.075125
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