›› 2014, Vol. 23 ›› Issue (12): 127401-127401.doi: 10.1088/1674-1056/23/12/127401

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Thermodynamics around magnetic phase transitions in alternating double-chain spin systems

丁林杰, 钟园, 樊帅伟, 朱丽娅   

  1. Department of Physics, China Three Gorges University, Yichang 443002, China
  • 收稿日期:2014-05-21 修回日期:2014-07-26 出版日期:2014-12-15 发布日期:2014-12-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11204157, 11174179, and 11247020), the Hubei Provincial Natural Science Foundation, China (Grant No. D20131307), and the China Three Gorges University Project (Grant No. KJ2011B068).

Thermodynamics around magnetic phase transitions in alternating double-chain spin systems

Ding Lin-Jie (丁林杰), Zhong Yuan (钟园), Fan Shuai-Wei (樊帅伟), Zhu Li-Ya (朱丽娅)   

  1. Department of Physics, China Three Gorges University, Yichang 443002, China
  • Received:2014-05-21 Revised:2014-07-26 Online:2014-12-15 Published:2014-12-15
  • Contact: Ding Lin-Jie E-mail:dinglinjie82@126.com
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11204157, 11174179, and 11247020), the Hubei Provincial Natural Science Foundation, China (Grant No. D20131307), and the China Three Gorges University Project (Grant No. KJ2011B068).

摘要: The thermodynamics and quantum phase transitions of two typically alternating double-chain systems are investigated by Green's function theory. (i) For the completely antiferromagnetic (AFM) alternating double-chain, the low-temperature antiferromagnetism with gapped behavior is observed, which is in accordance with the experimental result. In a magnetic field, we unveil the ground state phase diagram with zero plateau, 1/2 plateau, and polarized ferromagnetic (FM) phases, as a result of the intra-cluster spin-singlet competition. Furthermore, the Grüneisen ratio is an excellent tool to identify the quantum criticality and testify various quantum phases. (ii) For the antiferromagnetically coupled FM alternating chains, the 1/2 magnetization plateau and double-peak structure of specific heat appear, which are also observed experimentally. Nevertheless, the M–h curve shows an anomalous behavior in an ultra-low field, which is ascribed to the effectively weak Haldane-like state, demonstrated by the two-site entanglement entropy explicitly.

关键词: thermodynamics, quantum phase transition, double-chain spin system

Abstract: The thermodynamics and quantum phase transitions of two typically alternating double-chain systems are investigated by Green's function theory. (i) For the completely antiferromagnetic (AFM) alternating double-chain, the low-temperature antiferromagnetism with gapped behavior is observed, which is in accordance with the experimental result. In a magnetic field, we unveil the ground state phase diagram with zero plateau, 1/2 plateau, and polarized ferromagnetic (FM) phases, as a result of the intra-cluster spin-singlet competition. Furthermore, the Grüneisen ratio is an excellent tool to identify the quantum criticality and testify various quantum phases. (ii) For the antiferromagnetically coupled FM alternating chains, the 1/2 magnetization plateau and double-peak structure of specific heat appear, which are also observed experimentally. Nevertheless, the M–h curve shows an anomalous behavior in an ultra-low field, which is ascribed to the effectively weak Haldane-like state, demonstrated by the two-site entanglement entropy explicitly.

Key words: thermodynamics, quantum phase transition, double-chain spin system

中图分类号:  (Thermodynamic properties)

  • 74.25.Bt
75.30.Kz (Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)) 75.10.Pq (Spin chain models)