Anomalous behavior of folded phonon in spin-Peierls compound CuGeO3

Far-infrared magneto-optical studies were performed on the pure and doped CuGeO3 to investigate the field dependence of the folded phonon at 98 cm(-1) in the dimerized (D) and the incommensurate (IC) phases. The splitting of the folded mode into two components in the IC phase was observed in the pure and doped samples. The field dependence of the splitting can be scaled by that of the incommensurability, which was estimated by the X-ray diffraction experiments, (C) 2000 Elsevier Science B.V. All rights reserved.