Lattice Vibration Spectra in One-Dimensional Conductors**Projects supported partially by Chinese Natural Science Foundation and partially by Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Shanghai, China

Abstract

For one-dimensional conductors with half-filled band, the lattice vibration spectra, both acoustic and optical branches, are obtained analytically in the dimerized state. It is shown that, there exist not only a gap in Brillouin zone boundary, but also a gap between the optical and acoustic phonon branches when the electron-lattice coupling constant is Larger than . Then, the frequency of the Staggered mode around solitons can be described analytically for any coupling constant .