The dynamical properties of spin-1 and spin-1/2 antiferromagnetic Heisenberg chains (AHC's) are studied by diagonalizing exactly clusters of up to 18 and 26 sites, respectively. It is shown that the spin-1 AHC has a quasi-single-mode spectrum for momentum k\ensuremath{\ge}0.3\ensuremath{\pi}, while the low-energy edge of the spin-1/2 AHC is dominated by a spin-wave continuum. The dispersion curve obtained for the spin-1 chain is in excellent agreement with recent experiments on Ni( ${\mathrm{C}}_{2}$ ${\mathrm{H}}_{8}$ ${\mathrm{N}}_{2}$ ${)}_{2}$ ${\mathrm{NO}}_{2}$ ${\mathrm{ClO}}_{4}$ . The size dependence of the low-energy spectral weights is also analyzed.The dynamical properties of spin-1 and spin-1/2 antiferromagnetic Heisenberg chains (AHC's) are studied by diagonalizing exactly clusters of up to 18 and 26 sites, respectively. It is shown that the spin-1 AHC has a quasi-single-mode spectrum for momentum k\ensuremath{\ge}0.3\ensuremath{\pi}, while the low-energy edge of the spin-1/2 AHC is dominated by a spin-wave continuum. The dispersion curve obtained for the spin-1 chain is in excellent agreement with recent experiments on Ni(${\mathrm{C}}_{2}$${\mathrm{H}}_{8}$${\mathrm{N}}_{2}$${)}_{2}$${\mathrm{NO}}_{2}$${\mathrm{ClO}}_{4}$. The size dependence of the low-energy spectral weights is also analyzed.

Physical review. B, Condensed matterAug 1, 199330 citations

Spin dynamics of a Heisenberg antiferromagnetic chain

Roger Arthur Cowley, D. M. Tennant, T. G. Perring +2 more

Physica A Statistical Mechanics and its ApplicationsMar 1, 19933 citations

Dynamics of the classical antiferromagnetic Heisenberg chain in an applied field

Hans A. De Raedt, Bart De Raedt

A theoretical study of the low-temperature dynamics of the antiferromagnetic Heisenberg chain in an external field is presented. The time- and frequency-dependent transverse and longitudinal spin fluctuations and energy fluctuations are calculated by means of a continued fraction representation. The frequency moments are evaluated analytically by a computer program. The transfer-operator technique is used to calculate all static correlation functions. For modest magnetic fields, a two-peak structure in the dynamic form factor of the transverse spin fluctuations is observed. Apart from the usual spin-wave excitations, the longitudinal-spin-fluctuation spectra show a broad second resonance for some temperatures and fields. The energy fluctuations display a dominant oscillatory time dependence.A theoretical study of the low-temperature dynamics of the antiferromagnetic Heisenberg chain in an external field is presented. The time- and frequency-dependent transverse and longitudinal spin fluctuations and energy fluctuations are calculated by means of a continued fraction representation. The frequency moments are evaluated analytically by a computer program. The transfer-operator technique is used to calculate all static correlation functions. For modest magnetic fields, a two-peak structure in the dynamic form factor of the transverse spin fluctuations is observed. Apart from the usual spin-wave excitations, the longitudinal-spin-fluctuation spectra show a broad second resonance for some temperatures and fields. The energy fluctuations display a dominant oscillatory time dependence.

Physical review. B, Condensed matterJan 1, 198016 citations

High-field spin dynamics of antiferromagnetic quantum spin chains

M. Enderle, L. P. Régnault, C. Broholm +5 more

Physica B Condensed MatterMar 1, 20006 citations

{\mathrm{C}}_{2}

{\mathrm{H}}_{8}

{\mathrm{N}}_{2}

{)}_{2}

{\mathrm{NO}}_{2}

{\mathrm{ClO}}_{4}

. The size dependence of the low-energy spectral weights is also analyzed.