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arXiv · 1909.12704

Fragile 3D Order in V$_{1-x}$Mo$_x$O$_2$

Matthew A. Davenport·Matthew J. Krogstad·Logan M. Whitt·Chaowei Hu·Tyra C. Douglas·Ni Ni·Stephan Rosenkranz·Raymond Osborn·Jared M. Allred
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Abstract

The metal-to-insulator transition (MIT) in rutile VO$_2$ has proven uniquely difficult to characterize because of the complex interplay between electron correlations and atomic structure. Here we report the discovery of the sudden collapse of three-dimensional order in the low-temperature phase of V$_{1-x}$Mo$_x$O$_2$ at $x=0.17$ and the emergence of a novel frustrated two-dimensional order at $x=0.19$, with only a slight change in electronic properties. Single crystal diffuse x-ray scattering reveals that this transition from the 3D M1 phase to a 2D variant of the M2 phase results in long-range structural correlations along symmetry-equivalent (11L) planes of the tetragonal rutile structure, yet extremely short-range correlations transverse to these planes. These findings suggest that this two-dimensionality results from a novel form of geometric frustration that is essentially structural in origin.

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Matthew A. Davenport, Matthew J. Krogstad, Logan M. Whitt, Chaowei Hu, Tyra C. Douglas, Ni Ni, Stephan Rosenkranz, Raymond Osborn, Jared M. Allred. 2019-09-27. Fragile 3D Order in V$_{1-x}$Mo$_x$O$_2$. https://doi.org/10.1103/physrevlett.127.125501

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