Dynamics of the Distorted Diamond Chain
Abstract
We present results on the dynamics of the distorted diamond chain, S=1/2 dimers alternating with single spins 1/2 and exchange couplings J1 and J3 in between. The dynamics in the spin fluid (SF) and tetramer-dimer (TD) phases is investigated numerically by exact diagonalisation for up to 24 spins. Representative excitation spectra are presented, both for zero magnetic field and in the 1/3 plateau phase and the relevant parameters are determined across the phase diagram. The behavior across the SF-TD phase transition line is discussed for the specific heat and for excitation spectra. The relevance of the distorted diamond chain model for the material Cu3(CO3)2(OH)2 (azurite) is discussed with particular emphasis on inelastic neutron scattering experiments, a recent suggestion of one possibly ferromagnetic coupling constant is not confirmed.