Phonon anharmonicity in zirconium tungstate single crystal investigated by broadband light scattering. (19th September 2017)

• Record Type: Journal Article
• Authors: Oishi, Eiichi; Fujii, Yasuhiro; Katayama, Daisuke; Koreeda, Akitoshi; Nagakubo, Akira; Ogi, Hirotsugu
• Is Part Of: Japanese journal of applied physics. Volume 56:Number 10(2017)Supplement
• Publication Date: 2017-09-19
• Subjects: Physics -- Periodicals; 621.05
• DOI: 10.7567/JJAP.56.10PB06
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: We measured light scattering in a single crystal of ZrW2 O8 (ZWO) in the frequency range between 0.1 and 1100 cm −1 and in the temperature range between 3.5 and 300 K. From the temperature dependence of the optical and acoustic phonon frequencies, we found that low-frequency phonon modes below 100 cm −1 have large relative temperature coefficients (total anharmonicity values). The longitudinal acoustic mode, whose Brillouin light scattering has not been reported thus far, was found to have the largest negative total anharmonicity in a wide temperature range, indicating the possibility that the acoustic modes, as well as the low-frequency optical modes that are associated with the motions of WO4 and ZrO6 polyhedra, should contribute to the negative thermal expansion of ZWO.