中国物理B ›› 2012, Vol. 21 ›› Issue (3): 39101-039101.doi: 10.1088/1674-1056/21/3/039101

• • 上一篇    

何满潮,赵健,方志杰   

  • 收稿日期:2011-10-12 修回日期:2011-11-03 出版日期:2012-02-15 发布日期:2012-02-15
  • 通讯作者: 何满潮,hemanchao@263.net E-mail:hemanchao@263.net

First-principles study of atomic and electronic structures of kaolinite in soft rock

He Man-Chao(何满潮)†, Zhao Jian(赵健), and Fang Zhi-Jie(方志杰)   

  1. State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Beijing 100083, China
  • Received:2011-10-12 Revised:2011-11-03 Online:2012-02-15 Published:2012-02-15
  • Contact: He Man-Chao,hemanchao@263.net E-mail:hemanchao@263.net
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 40972196).

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Abstract: Kaolinite is a kind of clay mineral which often causes large deformations in soft-rock tunnel engineering and thus causes safety issues. To deal with these engineering safety issues, the physical/chemical properties of the kaolinite should be studied from basic viewpoints. By using the density-functional theory, in this paper, the atomic and the electronic structures of the kaolinite are studied within the local-density approximation (LDA). It is found that the kaolinite has a large indirect band gap with the conduction band minimum (CBM) and the valence band maximum (VBM) being at the $\varGamma$ and the B points, respectively. The chemical bonding between the cation and the oxygen anion in kaolinite is mainly ionic, accompanied by a minor covalent component. It is pointed that the VBM and the CBM of kaolinite consist of oxygen 2p and cation s states, respectively. The bond lengths between different cations and anions, as well as of the different OH groups, are also compared.

Key words: kaolinite, crystal structure, first-principles method

中图分类号:  (Crystal structure and defects, microstructure)

  • 91.60.Ed
71.15.Mb (Density functional theory, local density approximation, gradient and other corrections)