Spin Gap and Spin-Phonon Interaction in CuGeO_3
Abstract
We study the spin-Peierls transition in CuGeO3 by means of Raman-scattering. Improved measurements in the frequency range from 6 to 650 cm-1 at temperatures between 2 and 300 K show: a) directly the opening of a gap associated with the spin-Peierls transition and a continuous excitation above that gap, b) a discrete excitation within the gap, c) the existence of the well-known low-temperature peak at 230 cm-1 at temperatures above Tc = 14.3 K up to T ≈ 30 K, d) a pronounced Fano-type lineshape for the 105 cm-1 peak possibly due to spin-phonon interaction, and e) additional peaks related to the low-temperature phase at 260, 278, 416, 432, and 568 cm-1, which have not been reported yet. The structure of the low-temperature Raman-spectra can consistently be explained in terms of 2-magnon scattering.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1996
- Bibcode:
- 1996APS..MAR..I905L