Investigation of the Spin-Peierls transition in CuGeO_3 by Raman scattering

P. Lemmens; B. Eisener; M. Brinkmann; L. V. Gasparov; G. Güntherodt; P. v. Dongen; W. Richter; M. Weiden; C. Geibel; F. Steglich

doi:10.1016/0921-4526(96)00166-4

paper

Investigation of the Spin-Peierls transition in CuGeO_3 by Raman scattering

arXiv:cond-mat/9604181 · doi:10.1016/0921-4526(96)00166-4

Abstract

Raman experiments on the spin-Peierls compound CuGeO $_{3}$ and the substituted (Cu $_{1 - x}$ ,Zn $_{x}$ )GeO $_{3}$ and Cu(Ge $_{1 - x}$ ,Ga $_{x}$ )O $_{3}$ compounds were performed in order to investigate the response of specific magnetic excitations of the one-dimensional spin-1/2 chain to spin anisotropies and substitution-induced disorder. In pure CuGeO $_{3}$ , in addition to normal phonon scattering which is not affected at all by the spin-Peierls transition, four types of magnetic scattering features were observed. Below T $_{S P}$ =14 K a singlet-triplet excitation at 30 cm $^{- 1}$ , two-magnon scattering from 30 to 227 cm $^{- 1}$ and folded phonon modes at 369 and 819 cm $^{- 1}$ were identified. They were assigned by their temperature dependence and lineshape. For temperatures between the spin-Peierls transition T $_{S P}$ and approximately 100 K a broad intensity maximum centered at 300 cm $^{- 1}$ is observed.

7 pages, LaTex2e, including 3 figures (eps) to be published in Physica B (1996)