Dynamical properties of S=1 bond-alternating Heisenberg chains in transverse magnetic fields

Abstract

We calculate dynamical structure factors of the S=1 bond-alternating Heisenberg chain with a single-ion anisotropy in transverse magnetic fields, using a continued fraction method based on the Lanczos algorithm. In the Haldane-gap phase and the dimer phase, dynamical structure factors show characteristic field dependence. Possible interpretations are discussed. The numerical results are in qualitative agreement with recent results for inelastic neutron-scattering experiments on the S=1 bond-alternating Heisenberg-chain compound $\mathrm{Ni}({\mathrm{C}}_9{\mathrm{D}}_{24}{\mathrm{N}}_4)(\mathrm{N}{\mathrm{O}}_2)\mathrm{Cl}{\mathrm{O}}_4$ and the S=1 Haldane-gap compound $\mathrm{Ni}({\mathrm{C}}_5{\mathrm{D}}_{14}{\mathrm{N}}_2{)}_2{\mathrm{N}}_3(\mathrm{P}{\mathrm{F}}_6)$ in transverse magnetic fields.

7 pages, 6 figures