The exact solution of the edge-modified kekulene-like nanostructure Ising-Heisenberg spin system

Abstract

A ferromagnetic model of kekulene-like nanostructure is established, in which the Ising ring (S = 1) decorated by the edge-spin (S = 3/2) through antiferromagnetic Heisenberg exchange interaction. The thermodynamic properties and magnetization behavior of the system were investigated by use of the exact diagonalization and transfer matrix method . It was found that there are six different phases with different values of magnetic susceptibility multiplied by temperature at low temperature in the parameter space of single-ion anisotropy, but it gets only one value taken in the high-temperature limit. The multi-peak phenomena of the specific heat curve at ultra-low temperature are corresponding to the entropy of the system, which the abundant and dense excited states are near the ground state. It shows many different magnetization plateaus in the magnetization process of the system, but no spontaneous magnetization appears. The number and width of magnetization plateaus and the saturation of the magnetization are affected by the single-ion anisotropy. • The edge-modified kekulene-like nanostructure Ising-Heisenberg spin-(1,3/2) system has been exactly determined. • There are six different phases with different values of the magnetic susceptibility multiplied by temperature at low temperature in the parameter space of single-ion anisotropy, but it gets only one value taken in the high-temperature limit. • The multi-peak phenomena of the specific heat curve at ultra-low temperature are corresponding to the entropy of the system, which the abundant and dense excited states near the ground state. • The magnetization of the system shows many different jumps (magnetic plateaus) with the external magnetic field increasing.