The origin of the metal-to-insulator transition (MIT) in rutile VO2 has been studied for many decades. The importance of electron correlations, the nature of related structural phases, and other details have all been contested. Recent work characterizing the parent phase’s structural instability has emphasized its core role in the MIT. However, the relationship between the parent phase and related phases accessed through chemical substitution is still not understood, especially as they pertain to the structural order parameter and short-range atomic correlations. Electron doping in the form of Mo4+ suppresses the structural instability and enhances the metallic properties, unlike Cr3+, which localizes the electronic states and creates new insulating phases. Using diffuse scattering analysis derived from the total x-ray scattering on single crystals of V1-xMoxO2, we show that a critical concentration of Mo leads to a novel type of two-dimensionally ordered phase, among other new features. This characterization is consistent with a frustrated structural instability in the rutile crystal structure.

Medium range 2D order and structural frustration in doped VO2 revealed by diffuse x-ray scattering

2019 Spring National Meeting

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