Spin-phonon coupled modes in the incommensurate phases of doped CuGeO${}_3$

Abstract

The doping effect of the folded phonon mode at 98 cm${}^{-1}$ was investigated on the Si-doped CuGeO${}_3$ by magneto-optical measurements in far-infrared (FIR) region under high magnetic field. The folded phonon mode at 98 cm${}^{-1}$ appears not only in the dimerized (D) phase but also in the dimerized-anitiferromagnetic (DAF) phase on the doped CuGeO${}_3$. The splitting was observed in the incommensurate (IC) phase and the antiferromagnetically ordered incommensurate (IAF) phase above $H_C$. The split-off branches exhibit different field dependence from that of the pure CuGeO${}_3$ in the vicinity of $H_C$, and the discrepancy in the IAF phase is larger than that in the IC phase. It is caused by the interaction between the solitons and the impurities.

7 pages, 4 figures, resubmitted to Phys. Rev. B

References in corpus (4)

• NMR imaging of the soliton lattice profile in the spin-Peierls compound CuGeO_3
• Neutron scattering study of the field-induced soliton lattice in CuGeO${}_3$
• Thermal conductivity of pure and Mg-doped CuGeO_3 in the incommensurate phase
• Far-Infrared Spectroscopy in Spin-Peierls Compound CuGeO_3 under High Magnetic Fields