中国物理B ›› 2022, Vol. 31 ›› Issue (6): 60504-060504.doi: 10.1088/1674-1056/ac4e0b

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Thermodynamic properties of two-dimensional charged spin-1/2 Fermi gases

Jia-Ying Yang(杨家营)1, Xu Liu(刘旭)1, Ji-Hong Qin(秦吉红)1,2,†, and Huai-Ming Guo(郭怀明)3   

  1. 1 Department of Physics, University of Science and Technology Beijing, Beijing 100083, China;
    2 Institute of Theoretical Physics, University of Science and Technology Beijing, Beijing 100083, China;
    3 Department of Physics, Beihang University, Beijing 100191, China
  • 收稿日期:2021-12-28 接受日期:2022-01-24 出版日期:2022-05-17 发布日期:2022-05-19
  • 通讯作者: Ji-Hong Qin E-mail:jhqin@sas.ustb.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 11774019) and the Fundamental Research Funds for the Central Universities, China (Grant No. FRF-BR-16-014A).

Thermodynamic properties of two-dimensional charged spin-1/2 Fermi gases

Jia-Ying Yang(杨家营)1, Xu Liu(刘旭)1, Ji-Hong Qin(秦吉红)1,2,†, and Huai-Ming Guo(郭怀明)3   

  1. 1 Department of Physics, University of Science and Technology Beijing, Beijing 100083, China;
    2 Institute of Theoretical Physics, University of Science and Technology Beijing, Beijing 100083, China;
    3 Department of Physics, Beihang University, Beijing 100191, China
  • Received:2021-12-28 Accepted:2022-01-24 Online:2022-05-17 Published:2022-05-19
  • Contact: Ji-Hong Qin E-mail:jhqin@sas.ustb.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 11774019) and the Fundamental Research Funds for the Central Universities, China (Grant No. FRF-BR-16-014A).

摘要: Based on the mean-field theory, we investigate the thermodynamic properties of the two-dimensional (2D) charged spin-1/2 Fermi gas. Landé factor g is introduced to measure the strength of the paramagnetic effect. There is a competition between diamagnetism and paramagnetism in the system. The larger the Landé factor, the smaller the entropy and specific heat. Diamagnetism tends to increase the entropy, while paramagnetism leads to the decrease of the entropy. We find that there exists a critical value of Landé factor for the transition point due to the competition. The entropy of the system increases with the magnetic field when g < 0.58. With the growth of paramagnetism, when g > 0.58, the entropy first decreases with the magnetic field, then reaches a minimum value, and finally increases again. Both the entropy and specific heat increase with the temperature, and no phase transition occurs. The specific heat tends to a constant value at the hightemperature limit, and it approaches to zero at very low temperatures, which have been proved by the analytical calculation.

关键词: Fermi gas, entropy, specific heat, Landé, factor

Abstract: Based on the mean-field theory, we investigate the thermodynamic properties of the two-dimensional (2D) charged spin-1/2 Fermi gas. Landé factor g is introduced to measure the strength of the paramagnetic effect. There is a competition between diamagnetism and paramagnetism in the system. The larger the Landé factor, the smaller the entropy and specific heat. Diamagnetism tends to increase the entropy, while paramagnetism leads to the decrease of the entropy. We find that there exists a critical value of Landé factor for the transition point due to the competition. The entropy of the system increases with the magnetic field when g < 0.58. With the growth of paramagnetism, when g > 0.58, the entropy first decreases with the magnetic field, then reaches a minimum value, and finally increases again. Both the entropy and specific heat increase with the temperature, and no phase transition occurs. The specific heat tends to a constant value at the hightemperature limit, and it approaches to zero at very low temperatures, which have been proved by the analytical calculation.

Key words: Fermi gas, entropy, specific heat, Landé, factor

中图分类号:  (Quantum statistical mechanics)

  • 05.30.-d
05.30.Fk (Fermion systems and electron gas) 75.20.-g (Diamagnetism, paramagnetism, and superparamagnetism)