Fizika Nizkikh Temperatur: Volume 44, Number 2 (February 2018), p. 197-207    ( to contents , go back )

IR reflection and absorption spectra in CsDy(MoO4)2 at cooperative Jahn–Teller effect

V.I. Kutko, N.M. Nesterenko, N.S. Zubenko, S.N. Poperezhai, K.V. Kutko, and A.V. Eremenko

B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Nauky Ave., Kharkiv 61103, Ukraine
E-mail: nesterenko@ilt.kharkov.ua

Received Jule 7, 2017

Abstract

IR and FIR reflection and absorption spectra of the layered crystal CsDy(MoO4)2 are measured at a temperature range of 6–300 K. The changes are discussed found in the phonon spectra at the low-temperature phase transition and the characteristic vibrations also that provoke a collective instability of the type of the cooperative Jahn–Teller effect in CsDy(MoO4)2 and in the other layered alkali-rare-earth molybdates. At the discussion of the FIR spectra in CsDy(MoO4)2, we used data obtained in the frequency range 16–40 cm–1 for RbDy(MoO4)2.

PACS: 78.30.–j Infrared and Raman spectra;
PACS: 75.25.Dk Orbital, charge, and other orders, including coupling of these orders;
PACS: 71.70.Ej Spin-orbit coupling, Zeeman and Stark splitting, Jahn–Teller effect.

Key words: layered crystals, cooperative pseudo Jahn–Teller effect, vibrations spectrum.

Published online: December 26, 2017

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