中国物理B ›› 1998, Vol. 7 ›› Issue (11): 851-863.doi: 10.1088/1004-423X/7/11/007

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A DISCRETE VARIATIONAL METHOD STUDY ON THE ELECTRONIC STRUCTURES OF CaMnO3 AND LaMnO3

杨中芹, 孙强, 叶令, 谢希德   

  1. State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, China
  • 收稿日期:1998-03-16 修回日期:1998-06-01 出版日期:1998-11-20 发布日期:1998-11-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China under the Grant No. 19677202, and also by the National Climbing Program of China under the Grant No. 95-YU-41.

A DISCRETE VARIATIONAL METHOD STUDY ON THE ELECTRONIC STRUCTURES OF CaMnO3 AND LaMnO3

Yang Zhong-qin (杨中芹), Sun Qiang (孙强), Ye Ling (叶令), Xie Xi-de (谢希德)   

  1. State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, China
  • Received:1998-03-16 Revised:1998-06-01 Online:1998-11-20 Published:1998-11-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China under the Grant No. 19677202, and also by the National Climbing Program of China under the Grant No. 95-YU-41.

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摘要： The electronic structures of the perovskite oxides, LaMnO3 and CaMnO3, with various magnetic structures are studied using the first-principles discrete variational (DV) cluster method based on ab initio local-spin-density approximation (LSDA). The ground states of different magnetic phases (including ferromagnetic (FM), A-type antiferromagnetic (A-AFM), and G-type antiferromagnetic (G-AFM)) have been described in this work. The cubic CaMnO3 with observed G-AFM magnetic order is found to have a 0.1 eV calculated gap. Both FM CaMnO3 and LaMnO3 have "half-metallic" character, which is in agreement with other works. LaMnO3 with both A-type and G-type antiferromagnetic order have metallic band structures. Part of Jahn-Teller (JT) distortion (Q2 type) has been taken into consideration for A-AFM LaMnO3. Under Q2 type JT distortion, the occupied and unoccupied states of O 2p and Mn 3d states move farther away from the Fermi energy. It is also found that the distortion can further stabilize the structure. The density of states and the binding energy of the distorted A-AFM LaMnO3 are given in this paper.

Abstract: The electronic structures of the perovskite oxides, LaMnO3 and CaMnO3, with various magnetic structures are studied using the first-principles discrete variational (DV) cluster method based on ab initio local-spin-density approximation (LSDA). The ground states of different magnetic phases (including ferromagnetic (FM), A-type antiferromagnetic (A-AFM), and G-type antiferromagnetic (G-AFM)) have been described in this work. The cubic CaMnO3 with observed G-AFM magnetic order is found to have a 0.1 eV calculated gap. Both FM CaMnO3 and LaMnO3 have "half-metallic" character, which is in agreement with other works. LaMnO3 with both A-type and G-type antiferromagnetic order have metallic band structures. Part of Jahn-Teller (JT) distortion (Q2 type) has been taken into consideration for A-AFM LaMnO3. Under Q2 type JT distortion, the occupied and unoccupied states of O 2p and Mn 3d states move farther away from the Fermi energy. It is also found that the distortion can further stabilize the structure. The density of states and the binding energy of the distorted A-AFM LaMnO3 are given in this paper.

中图分类号: 

  • 75.25.+z
71.20.Ps (Other inorganic compounds) 71.15.Mb (Density functional theory, local density approximation, gradient and other corrections) 75.50.Dd (Nonmetallic ferromagnetic materials) 75.50.Ee (Antiferromagnetics)