Issue 31, 2020

A crystallographic approach to the short-range ordering problem in V1−xMoxO2 (0.50 ≤ x ≤ 0.60)

Abstract

The V1−xMoxO2 phase diagram has high structural and electronic complexity that is driven by strong, short-range correlations that compete with the long-range rutile crystal structure. The substitution regime near 50% Mo occupancy is no exception, but there has so far been no significant progress in determining the actual structure. Reported here is a combined study using single crystal X-ray diffraction, powder X-ray diffraction, and representational analysis to examine both the local and crystallographically averaged atomic structures simultaneously near x = 0.50. Between about x = 0.50 and 0.60, the average structure of V1−xMoxO2 is the parent rutile phase, but the local symmetry is broken by atomic displacements that are best described using the orthorhombic subgroup Fmmm. This model is locally similar to the two-dimensionally ordered 2D-M2 phase recently reported in the compositional range 0.19 ≤ x ≤ 0.30, except the correlation length is much shorter in the 2D plane, and longer in the frustrated one, making it more isotropic. This work also extends the 2D-M2 phase regime up to x = 0.43, and suggests that the local-Fmmm phase observed here can be seen as the end result of the continued suppression of the 2D-M2 phase through enhanced geometric frustration between the intrinsic order parameters. This suggests that other doped-rutile phases with elusive structures may also be dominated by similar short-range correlations that are hidden in the diffuse scattering.

Graphical abstract: A crystallographic approach to the short-range ordering problem in V1−xMoxO2 (0.50 ≤ x ≤ 0.60)

Supplementary files

Article information

Article type
Paper
Submitted
06 Mac 2020
Accepted
02 Jul 2020
First published
03 Jul 2020

J. Mater. Chem. C, 2020,8, 10907-10916

Author version available

A crystallographic approach to the short-range ordering problem in V1−xMoxO2 (0.50 ≤ x ≤ 0.60)

M. A. Davenport and J. M. Allred, J. Mater. Chem. C, 2020, 8, 10907 DOI: 10.1039/D0TC01173H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements