The exact solution of the edge-modified graphene nanoribbon-like structure Ising-Heisenberg spin (1,1/2) system

Abstract

A two-fold rotational symmetry ferromagnetic Ising-Heisenberg model modified by edge spin ( S = 1 / 2 ) with antiferromagnetic Heisenberg exchange interaction, whose shape is graphene nanoribbon-like has been constructed, and the host Ising spin ( S = 1 ). By use of the star-triangle transformation and the transfer matrix method, the edge states, thermodynamics and magnetization behavior of the system display various properties. The results perform that the unique edge-spin states and the host-spin states of the system are influenced with each other. And there are eleven different ground state phases, which are presented as the values of magnetic susceptibility multiplied by temperature at ultra-low temperature in the parameter space of single-ion anisotropy and antiferromagnetic Heisenberg interaction. Because of a large number of excited states close to the ground state, the specific heat curve shows multi-peak phenomena, which are analyzed by corresponding to the entropy of the system. The magnetization process of the system is complex, due to the direct correlation of the edge-spin states and the host-spin states of system, in which many different magnetization plateaus appear. The rigorous results of the number and width of magnetization plateaus and the saturation of the magnetization are written. This study offers unique opportunities for future technological applications such as proposed designs of graphene-based quantum spintronic devices as well as magnetic ordering.