Local Structures and Ordering Processes in Two-Dimensional Regularly-Frustrated Models

概要

論文の詳細を見る
Phase transitions in two-dimensional regularly-frustrated systems are studied by focussing attention on their local structures and ordering processes, in order to understand how frustration influences the phase transitions. In layered frustrated Ising models on a square lattice there occur phase transitions due to entropy gains and the system is regarded to consist of two kinds of regions which play different roles. The results obtained on the ordering are consistent with those rigorously obtained. In fully-frustrated anisotropic Heisenberg models on a triangular lattice, the Hamiltonians can be expressed in terms of composite spins each of which consists mainly of three nearest spins and is represented by two vectors (one of which is the chirality vector). The results obtained by using them in case of no external field well explains the ones obtained by Monte Carlo simulations. In a fully-frustrated plane rotator model on a honeycomb lattice the frustration is incompletely relaxed, and gives rise to extra degeneracy in the ground state as compared with the fully-frustrated models on other lattices.
理論物理学刊行会の論文
1987-01-20