Fragile 3D Order in V<sub>(1-x)</sub>Mo<sub>x</sub>O<sub>2</sub>
ORAL
Abstract
VO2 displays a 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 V0.81Mo0.19O2. In the low-temperature phase, sharp rods are observed, indicating two-dimensional ordering of atomic displacements. The 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.
Diffuse x-ray scattering measurements were performed on a single crystal of the V0.81Mo0.19O2. In the low-temperature phase, sharp rods are observed, indicating two-dimensional ordering of atomic displacements. The 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.
*This work was supported by the US DOE, Office of Science, Basic Energy Science, Materials Sciences and Engineering Division.
–
Presenters
-
Matthew Krogstad
- Materials Science Division, Argonne National Laboratory
- Argonne National Laboratory
- Materials Science Division, Argonne National Lab
- Material Science, Argonne National Laboratory
- Material Science Division, Argonne National Laboratory