Zero-Temperature Study of a Tetrameric Spin-1/2 Chain in a Transverse Magnetic Field

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• 作者：J. Vahedi ; M. Shabani Arbousara ; S. Mahdavifar
• 关键词：Spin ; 1/2 chain ; Alternating Heisenberg spin ; 1/2 ; Transverse magnetic field
• 刊名：Journal of Low Temperature Physics
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：186
• 期：3-4
• 页码：217-232
• 全文大小：
• 刊物类别：Physics and Astronomy
• 刊物主题：Condensed Matter Physics; Characterization and Evaluation of Materials; Magnetism, Magnetic Materials;
• 出版者：Springer US
• ISSN：1573-7357
• 卷排序：186

文摘

We consider an alternating Heisenberg spin-1/2 antiferromagnetic–ferromagnetic chain with the space-modulated dominant antiferromagnetic exchange and anisotropic ferromagnetic coupling (tetrameric spin-1/2 chain). The zero-temperature effect of a symmetry breaking transverse magnetic field on the model is studied numerically. It is found that the anisotropy effect on the ferromagnetic coupling induces two new gapped phases. We identified their orderings as a kind of the stripe antiferromagnetic phase. As a result, the magnetic phase diagram of the tetrameric chain shows five gapped quantum phases, and the system is characterized by four critical fields which mark quantum phase transitions in the ground state of the system with the changing transverse magnetic field. We have also exploited the well-known bipartite entanglement (name as concurrence) and global entanglement tools to verify the occurrence of quantum phase transitions and the corresponding critical points.