Fragile 3D Order in V$_{(1-x)}$Mo$_{x}$O$_{2}$

ORAL

Abstract

VO$_2$ displays a first-order metal-insulator phase transition near 340 K. Accompanying this electronic transition is a structural transition. The connection between these two transitions is unclear, with electronically-driven and structurally-driven models providing conflicting results. Electron doping via molybdenum substitution enhances metallicity and reduces the structural transition temperature; between 17% and 19% Mo, we find that the long-range structural transition is suppressed entirely while the electronic transitions remain similar. Diffuse x-ray scattering measurements were performed on a single crystal of the V$_0.81$Mo$_0.19$O$_2$. In the low-temperature insulating phase, sharp rods are observed, indicating two-dimensional ordering of atomic displacements. The slight oscillation of these rods about the [110] direction in reciprocal space can be explained by weak, inherently frustrated coupling between the ordered planes. Such fragile embedded order is predicted by an Ising-like ferrodistortive model proposed by Lovorn and Sarker. 3D-ΔPDF analysis of the diffuse scattering and structural simulations provide a clear picture of the locally ordered atomic displacements in this system.

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Authors

  • Matthew Krogstad

    Argonne National Laboratory

  • Dmitri Sergatskov

    J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506 USA, Department of Physics, Augustana University, Sioux Falls, SD 57197 USA, Northwestern University, Fermilab, University of Cambridge, Stanford University, Missouri State University - Dept. of Physics, Astronomy, and Materials Science, University of Alabama, Purdue University, Princeton, Illinois Institute of Technology, Argonne National Laboratory, Rutgers University, Stockholm University, University of Wisconsin, University of lowa, Oregon State University, Fermi National Accelerator Laboratory, New York University, University of Nevada, Reno, Retired

  • Dmitri Sergatskov

    J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506 USA, Department of Physics, Augustana University, Sioux Falls, SD 57197 USA, Northwestern University, Fermilab, University of Cambridge, Stanford University, Missouri State University - Dept. of Physics, Astronomy, and Materials Science, University of Alabama, Purdue University, Princeton, Illinois Institute of Technology, Argonne National Laboratory, Rutgers University, Stockholm University, University of Wisconsin, University of lowa, Oregon State University, Fermi National Accelerator Laboratory, New York University, University of Nevada, Reno, Retired

  • Stephan Rosenkranz

    Argonne National Laboratory

  • Raymond Osborn

    Argonne National Laboratory

  • Jared Allred

    University of Alabama