中国物理B ›› 2024, Vol. 33 ›› Issue (3): 36403-036403.doi: 10.1088/1674-1056/ad0cc7

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Comparative study on phase transition behaviors of fractional molecular field theory and random-site Ising model

Ting-Yu Liu(刘婷玉)1, Wei Zhao(赵薇)1, Tao Wang(王涛)1, Xiao-Dong An(安小冬)1, Lai Wei(卫来)1,†, and Yi-Neng Huang(黄以能)1,2,‡   

  1. 1 Xinjiang Laboratory of Phase Transitions and Microstructures in Condensed Matters, College of Physical Science and Technology, Yili Normal University, Yili 835000, China;
    2 National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210008, China
  • 收稿日期:2023-08-18 修回日期:2023-10-31 接受日期:2023-11-16 出版日期:2024-02-22 发布日期:2024-02-29
  • 通讯作者: Lai Wei, Yi-Neng Huang E-mail:lweiphy@sina.com;ynhuang@nju.edu.cn
  • 基金资助:
    Project supported by the Open Project of the Key Laboratory of Xinjiang Uygur Autonomous Region, China (Grant No. 2021D04015) and the Yili Kazakh Autonomous Prefecture Science and Technology Program Project, China (Grant No. YZ2022B021).

Comparative study on phase transition behaviors of fractional molecular field theory and random-site Ising model

Ting-Yu Liu(刘婷玉)1, Wei Zhao(赵薇)1, Tao Wang(王涛)1, Xiao-Dong An(安小冬)1, Lai Wei(卫来)1,†, and Yi-Neng Huang(黄以能)1,2,‡   

  1. 1 Xinjiang Laboratory of Phase Transitions and Microstructures in Condensed Matters, College of Physical Science and Technology, Yili Normal University, Yili 835000, China;
    2 National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210008, China
  • Received:2023-08-18 Revised:2023-10-31 Accepted:2023-11-16 Online:2024-02-22 Published:2024-02-29
  • Contact: Lai Wei, Yi-Neng Huang E-mail:lweiphy@sina.com;ynhuang@nju.edu.cn
  • Supported by:
    Project supported by the Open Project of the Key Laboratory of Xinjiang Uygur Autonomous Region, China (Grant No. 2021D04015) and the Yili Kazakh Autonomous Prefecture Science and Technology Program Project, China (Grant No. YZ2022B021).

摘要: Fractional molecular field theory (FMFT) is a phenomenological theory that describes phase transitions in crystals with randomly distributed components, such as the relaxor-ferroelectrics and spin glasses. In order to verify the feasibility of this theory, this paper fits it to the Monte Carlo simulations of specific heat and susceptibility versus temperature of two-dimensional (2D) random-site Ising model (2D-RSIM). The results indicate that the FMFT deviates from the 2D-RSIM significantly. The main reason for the deviation is that the 2D-RSIM is a typical system of component random distribution, where the real order parameter is spatially heterogeneous and has no symmetry of space translation, but the basic assumption of FMFT means that the parameter is spatially uniform and has symmetry of space translation.

关键词: phase transition, molecular field theory, Ising model, Monte Carlo

Abstract: Fractional molecular field theory (FMFT) is a phenomenological theory that describes phase transitions in crystals with randomly distributed components, such as the relaxor-ferroelectrics and spin glasses. In order to verify the feasibility of this theory, this paper fits it to the Monte Carlo simulations of specific heat and susceptibility versus temperature of two-dimensional (2D) random-site Ising model (2D-RSIM). The results indicate that the FMFT deviates from the 2D-RSIM significantly. The main reason for the deviation is that the 2D-RSIM is a typical system of component random distribution, where the real order parameter is spatially heterogeneous and has no symmetry of space translation, but the basic assumption of FMFT means that the parameter is spatially uniform and has symmetry of space translation.

Key words: phase transition, molecular field theory, Ising model, Monte Carlo

中图分类号:  (General theory of phase transitions)

  • 64.60.Bd
64.60.De (Statistical mechanics of model systems (Ising model, Potts model, field-theory models, Monte Carlo techniques, etc.)) 77.80.Jk (Relaxor ferroelectrics) 75.50.Lk (Spin glasses and other random magnets)