中国物理B ›› 2024, Vol. 33 ›› Issue (1): 16302-16302.doi: 10.1088/1674-1056/acfd18

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Determining Hubbard U of VO2 by the quasi-harmonic approximation

Longjuan Kong(孔龙娟), Yuhang Lu(陆雨航), Xinying Zhuang(庄新莹), Zhiyong Zhou(周志勇), and Zhenpeng Hu(胡振芃)   

  1. School of Physics, Nankai University, Tianjin 300071, China
  • 收稿日期:2023-07-18 修回日期:2023-09-22 接受日期:2023-09-26 出版日期:2023-12-13 发布日期:2023-12-28
  • 通讯作者: Zhenpeng Hu E-mail:zphu@nankai.edu.cn
  • 基金资助:
    This work was supported by the National Natural Science Foundation of China (Grant Nos. 21933006 and 21773124) and the Fundamental Research Funds for the Central Universities Nankai University (Grant Nos. 010-63233001, 63221346, 63213042, and ZB22000103). K.L. acknowledges the support from the China Postdoctoral Science Foundation (Grant No. 2021M691674) and the Hefei National Laboratory for Physical Sciences at the Microscale (Grant No. KF2020105).

Determining Hubbard U of VO2 by the quasi-harmonic approximation

Longjuan Kong(孔龙娟), Yuhang Lu(陆雨航), Xinying Zhuang(庄新莹), Zhiyong Zhou(周志勇), and Zhenpeng Hu(胡振芃)   

  1. School of Physics, Nankai University, Tianjin 300071, China
  • Received:2023-07-18 Revised:2023-09-22 Accepted:2023-09-26 Online:2023-12-13 Published:2023-12-28
  • Contact: Zhenpeng Hu E-mail:zphu@nankai.edu.cn
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (Grant Nos. 21933006 and 21773124) and the Fundamental Research Funds for the Central Universities Nankai University (Grant Nos. 010-63233001, 63221346, 63213042, and ZB22000103). K.L. acknowledges the support from the China Postdoctoral Science Foundation (Grant No. 2021M691674) and the Hefei National Laboratory for Physical Sciences at the Microscale (Grant No. KF2020105).

摘要: Vanadium dioxide VO2 is a strongly correlated material that undergoes a metal-to-insulator transition around 340 K. In order to describe the electron correlation effects in VO2, the DFT + U method is commonly employed in calculations. However, the choice of the Hubbard U parameter has been a subject of debate and its value has been reported over a wide range. In this paper, taking focus on the phase transition behavior of VO2, the Hubbard U parameter for vanadium oxide is determined by using the quasi-harmonic approximation (QHA). First-principles calculations demonstrate that the phase transition temperature can be modulated by varying the U values. The phase transition temperature can be well reproduced by the calculations using the Perdew—Burke—Ernzerhof functional combined with the U parameter of 1.5 eV. Additionally, the calculated band structure, insulating or metallic properties, and phonon dispersion with this U value are in line with experimental observations. By employing the QHA to determine the Hubbard U parameter, this study provides valuable insights into the phase transition behavior of VO2. The findings highlight the importance of electron correlation effects in accurately describing the properties of this material. The agreement between the calculated results and experimental observations further validates the chosen U value and supports the use of the DFT+U method in studying VO2.

关键词: quasi-harmonic approximation, vanadium dioxide, first-principles calculation, Hubbard U

Abstract: Vanadium dioxide VO2 is a strongly correlated material that undergoes a metal-to-insulator transition around 340 K. In order to describe the electron correlation effects in VO2, the DFT + U method is commonly employed in calculations. However, the choice of the Hubbard U parameter has been a subject of debate and its value has been reported over a wide range. In this paper, taking focus on the phase transition behavior of VO2, the Hubbard U parameter for vanadium oxide is determined by using the quasi-harmonic approximation (QHA). First-principles calculations demonstrate that the phase transition temperature can be modulated by varying the U values. The phase transition temperature can be well reproduced by the calculations using the Perdew—Burke—Ernzerhof functional combined with the U parameter of 1.5 eV. Additionally, the calculated band structure, insulating or metallic properties, and phonon dispersion with this U value are in line with experimental observations. By employing the QHA to determine the Hubbard U parameter, this study provides valuable insights into the phase transition behavior of VO2. The findings highlight the importance of electron correlation effects in accurately describing the properties of this material. The agreement between the calculated results and experimental observations further validates the chosen U value and supports the use of the DFT+U method in studying VO2.

Key words: quasi-harmonic approximation, vanadium dioxide, first-principles calculation, Hubbard U

中图分类号:  (First-principles theory)

  • 63.20.dk
63.22.-m (Phonons or vibrational states in low-dimensional structures and nanoscale materials) 63.20.D- (Phonon states and bands, normal modes, and phonon dispersion) 71.10.Fd (Lattice fermion models (Hubbard model, etc.))