Energy of bond defects in quantum spin chains obtained from local approximations and from exact diagonalization

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:320

Article; Proceedings Paper

Libero, V. L.¹  Capelle, K.¹  Souza, F. C.¹  Favaro, A. P.¹ 

[1] Univ Sao Paulo, Inst Fis Sao Carlos, BR-13560970 Sao Carlos, SP, Brazil

关键词: Heisenberg model;    magnetic impurities;    bond defects;    density-functional theory;    correlation energy;   

DOI  :  10.1016/j.jmmm.2008.02.187

来源: Elsevier

【 摘 要 】

We study the influence of ferromagnetic and antiferromagnetic bond defects on the ground-state energy of antiferromagnetic spin chains. In the absence of translational invariance, the energy spectrum of the full Hamiltonian is obtained numerically, by an iterative modi. cation of the power algorithm. In parallel, approximate analytical energies are obtained from a local-bond approximation, proposed here. This approximation results in significant improvement upon the mean-field approximation, at negligible extra computational effort. (C) 2008 Published by Elsevier B.V.

【 授权许可】

Free