This article is cited in 2 papers

Proceedings of the XIX All-Russian Conference on Physics of Ferroelectrics (VKS-XIX) (Moscow, Russia, June 19-23, 2011

Phonons and their dispersion in model ferroelastics Hg$_2$Hal$_2$

E. M. Roginskii^a, A. A. Kvasov^b, Yu. F. Markov^a, M. B. Smirnov<sup>b

a</sup> Ioffe Institute, St. Petersburg
^b Saint Petersburg State University

Abstract: Dispersion relations of the acoustic and optical phonon frequencies have been calculated and plotted, and the density of states of the phonon spectrum of Hg$_2$Cl$_2$ and Hg$_2$Br$_2$ crystals has been derived. The effect of hydrostatic pressure on the frequencies of acoustic and optical phonons and their dispersion has been theoretically analyzed. It has been found that an increase in the pressure leads to a strong softening of the slowest acoustic TA branch (the soft mode) at the X point of the Brillouin zone boundary, which is consistent with the phenomenological Landau theory and correlates with experiment.

 English version: Physics of the Solid State, 2012, 54:5, 900–904

Bibliographic databases:

•