Determination of Hamiltonian parameters of anisotropic one-dimensional quantum chains by susceptibility measurements

With the use of finite-chain calculations, the perpendicular and parallel susceptibilities of anisotropic $\mathrm{XXZ}$ chains have been determined in all parameter domains of the model. It is shown how these results can be used to extract the parameters $J$, $\Delta$, and $g$ of the model unambiguously. Application to published materials validates the approach. If one considers all three components of the susceptibility (${\chi }^{\parallel }$, ${\chi }^{\perp 1}$, ${\chi }^{\perp 2}$), they show a characteristic behavior in the different parameter regimes (ferromagnets and antiferromagnets, displaying planar- and uniaxial-anisotropic spin coupling, respectively). From the ratio $\frac{T_{max}^{\parallel }}{T_{max}^{\perp }}$ one can decide whether or not a given material is $\mathrm{XXZ}$-like.