Lattice dynamics of ASb(2)O(6) (A = Cu, Co) with trirutile structure

Author(s)

Maimone, D. T. ; Christian, A. B. ; Neumeier, J. J. ; Granado, E.

• Document type: Journal article
• Source: PHYSICAL REVIEW B; v. 97, n. 10, p. 10-pg., 2018-03-13.

Abstract

Raman spectroscopy experiments on single crystals of CuSb2O6 and CoSb2O6 quasi-one-dimensional antiferromagnets with trirutile crystal structure were performed, with a focus on the first material. The observed Raman-active phonon modes and previously reported infrared-active modes were identified with the aid of ab initio lattice dynamics calculations. The structural transition between monoclinic beta-CuSb2O6 and tetragonal alpha-CuSb2O6 phases at T-s = 400 K is manifested in our spectra by a "repulsion" of two accidentally quasidegenerate symmetric modes below T-s, caused by a phonon mixing effect that is only operative in the monoclinic beta-CuSb2O6 phase due to symmetry restrictions. Also, two specific phonons, associated with CuO6 octahedra rotation and with a Jahn-Teller elongation mode, soften and broaden appreciably as T -> T-s. A crossover from a displacive to an order-disorder transition at T-s is inferred. (AU)

• FAPESP's process: 12/04870-7 - Studies of novel complex and advanced materials
• Grantee: Pascoal Jose Giglio Pagliuso
• Support Opportunities: Research Projects - Thematic Grants