Dynamical properties of low-dimensional \(\) and \(\) spin-Peierls systems

摘要: Properties of low-dimensional spin-Peierls systems are described by using a one-dimensional S=1/2 antiferromagnetic Heisenberg chain linearly coupled to single phonon mode wave vector \(\) (whose contribution is expected be dominant). By exact diagonalizations small rings with up 24 sites supplemented finite size scaling analysis, static and dynamical properties investigated. Numerical evidences given for spontaneous discrete symmetry breaking towards spin gapped phase frozen lattice dimerization. Special emphasis put on the comparative study two inorganic compounds CuGeO3 NaV2O5 model parameters determined from fit experimental gaps. We predict that spin-phonon coupling 2 or 3 times larger in than CuGeO3. Inelastic neutron scattering spectra calculated similar results found approximation including In particular, magnon S=1 branch clearly separated continuum triplet excitations gap.