物理化学学报 >> 2011, Vol. 27 >> Issue (02): 388-394.doi: 10.3866/PKU.WHXB20110220

理论与计算化学 上一篇    下一篇

六角多铁性HoMnO3的电子和能带结构

仲崇贵1,2,3, 方靖淮1, 杨建华1, 董正超1,3, 江学范2   

  1. 1. 南通大学理学院, 江苏 南通 226007;
    2. 常熟理工学院先进功能材料省重点实验室, 江苏 常熟 225500;
    3. 苏州大学物理科学与技术学院, 江苏 苏州 215006
  • 收稿日期:2010-08-02 修回日期:2010-11-01 发布日期:2011-01-25
  • 通讯作者: 董正超, 仲崇贵 E-mail:dzc@ntu.edu.cn, chgzhong@ntu.edu.cn
  • 基金资助:

    国家自然科学基金(10974104, 50832002, 10874021, 30970754)和江苏省自然科学基金(BK2006047, BK2008183)及江苏省教育厅青蓝工程资助项目

Electronic and Band Structures of Hexagonal Multiferroic HoMnO3

ZHONG Chong-Gui1,2,3, FANG Jing-Huai1, YANG Jian-Hua1, DONG Zheng-Chao1,3, JIANG Xue-Fan2   

  1. 1. School of Sciences, Nantong University, Nantong 226007, Jiangsu Province, P. R. China;
    2. Jiangsu Key Laboratory of Advanced Functional Materials, Changshu Institute of Technology, Changshu, 215500, Jiangsu Province, P. R. China; 3School of Physical Sciences and Technology, Soochow University, Suzhou 215006, Jiangsu Province,P. R. China
  • Received:2010-08-02 Revised:2010-11-01 Published:2011-01-25
  • Contact: DONG Zheng-Chao, ZHONG Chong-Gui E-mail:dzc@ntu.edu.cn, chgzhong@ntu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (10974104, 50832002, 10874021, 30970754), Natural Science Foundation of Jiangsu Province, China (BK2006047, BK2008183), and Qing Lan Project of Education Department of Jiangsu Province, China.

摘要:

基于密度泛函理论(DFT)结合投影缀加平面波(PAW)方法, 运用广义梯度近似(GGA), 在考虑电子基态自旋阻挫非共线的磁性结构基础上, 研究了具有六角钙钛矿结构HoMnO3材料的磁性、电子和能带结构, 并解释了相关实验结果. 结果表明: 当考虑Mn3+离子的电子自旋在平面内呈阻挫的三角非共线反铁磁(NAFM)排列时, 六角HoMnO3的总能降低、能隙变大、磁矩增大、各原子的位置更接近于实验值, 电子态密度(DOS)分布具有与X光吸收谱测量更为一致的结果. 对非共线磁性结构计算得到的电子态密度和能带结构的分析发现, 实验中观察到的1.7和2.3 eV两个光学吸收峰都源于Mn3+离子3d与平面内O(3, 4) 2p形成的杂化态与Mn [3d3z2-r2]之间的电子跃迁, 而Ho 5d空轨道与平面上的O(3, 4) 2p轨道之间在z方向的强烈杂化驱动HoMnO3产生垂直于平面方向的铁电极化.

关键词: 反铁磁, 阻挫, 磁电, 杂化, 铁电

Abstract:

We investigated the magnetism, electronic and band structures of hexagonal HoMnO3 using density functional theory (DFT) within the generalized gradient approximation (GGA) and combined this with the projector augmented wave (PAW) method. The relative experimental results are explained using non-collinear magnetic structure calculations. The calculations show that the total energy of the unit cell decreases and the energy gap as well as magnetic moment of Mn3+ increases. Each atom coordinate was close to the experimentally measured values and the electronic densities of states of the HoMnO3 qualitatively agreed with the results from X-ray absorption spectroscopy, when the noncollinear triangular antiferromagnetic configurations of the Mn3+ ions in the ab plane were taken into account. According to the densities of states and band structure analysis, as calculated within the noncollinear magnetic structure, we found that the two experimentally determined optical absorption peaks near 1.7 and 2.3 eV were due to interband transitions between the oxygen states that hybridize strongly with different Mn orbitals and the Mn [3d3z2-r2] state. The strong orbital hybridization between Ho 5d and O(3, 4) 2p in the plane drives the ferroelectric polarization of the HoMnO3 to the ab plane.

Key words: Antiferromaget, Frustration, Magnetoelectricity, Hybridization, Ferroelectricity

MSC2000: 

  • O641.4