中国物理B ›› 2008, Vol. 17 ›› Issue (11): 4002-4008.doi: 10.1088/1674-1056/17/11/011
单传家, 程维文, 刘堂昆, 黄燕霞, 李宏
Shan Chuan-Jia (单传家), Cheng Wei-Wen (程维文), Liu Tang-Kun (刘堂昆), Huang Yan-Xia (黄燕霞), Li Hong (李宏)
摘要: By using the method of density-matrix renormalization-group to solve the different spin--spin correlation functions, the nearest-neighbouring entanglement (NNE) and the next-nearest-neighbouring entanglement (NNNE) of one-dimensional alternating Heisenberg XY spin chain are investigated in the presence of alternating the-nearest-neighbouring interaction of exchange couplings, external magnetic fields and the next-nearest neighbouring interaction. For a dimerised ferromagnetic spin chain, the NNNE appears only above a critical dimerized interaction, meanwhile, the dimerized interaction a effects a quantum phase transition point and improves the NNNE to a large extent. We also study the effect of ferromagnetic or antiferromagnetic next-nearest neighbouring (NNN) interaction on the dynamics of NNE and NNNE. The ferromagnetic NNN interaction increases and shrinks the NNE below and above a critical frustrated interaction respectively, while the antiferromagnetic NNN interaction always reduces the NNE. The antiferromagnetic NNN interaction results in a large value of NNNE compared with the case where the NNN interaction is ferromagnetic.
中图分类号: (Quantized spin models, including quantum spin frustration)