Direct Correlation of Structural Domain Formation with the Metal Insulator Transition in a VO₂ Nanobeam

Abstract

The electrical resistance of single VO2 nanobeams was measured while simultaneously mapping the domain structure with Raman spectroscopy to investigate the relationship between structural domain formation and the metal−insulator transition. With increasing temperature, the nanobeams transformed from the insulating monoclinic M1 phase to a mixture of the Mott-insulating M2 and metallic rutile phases. Domain fractions were used to extract the temperature dependent resistivity of the M2 phase, which showed an activated behavior consistent with the expected Mott−Hubbard gap. Metallic monoclinic phases were also produced by direct injection of charge into devices, decoupling the Mott metal−insulator transition from the monoclinic to rutile structural phase transition