Quantum Monte Carlo calculation for spin systems in alternating Heisenberg-bond chains

Abstract

The studies on the models of one dimensional spin = 1/2 systems including bond alternation with ferromagnetic and antiferromagnetic interactions were carried out. The energies, heat capacities, magnetic susceptibility and some kinds of correlation functions of the models described by the Hamiltonian have been calculated using a quantum Monte Carlo method. The figure of heat capacities versus temperature for the chain length L = 64 plotted by the results of the calculations were discussed in relation to the single shape maximum. The correlation functions in the system were studied to understand its magnetic properties, and both of the ferromagnetic correlation function as well as the antiferromagnetic one were calculated. The temperature dependence of the correlation functions was discussed.

強磁性および反強磁性相互作用を伴い結合交代を含む1次元1/2スピン系模型を研究した。ハミルトニアンで表される模型のエネルギー、熱容量、磁化率および相関関数を、量子モンテカルロ法を用いて計算した。チェーン長さL=64のときの熱容量に対する温度の関係について計算結果を図に表し、単一形最大値について論じた。磁気特性を知るために系の相関関数を検討し、強磁性ならびに反強磁性相関関数を計算した。相関関数の温度依存性を論じた。