中国物理B ›› 2017, Vol. 26 ›› Issue (12): 126103-126103.doi: 10.1088/1674-1056/26/12/126103

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

First-principles calculations of structure and elasticity of hydrous fayalite under high pressure

Chuan-Yu Zhang(张传瑜), Xu-Ben Wang(王绪本), Xiao-Feng Zhao(赵晓凤), Xing-Run Chen(陈星润), You Yu(虞游), Xiao-Feng Tian(田晓峰)   

  1. 1. College of Geophysics, Chengdu University of Technology, Chengdu 610059, China;
    2. College of Optoelectronic Technology, Chengdu University of Information Technology, Chengdu 610225, China;
    3. College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610059, China
  • 收稿日期:2017-06-14 修回日期:2017-09-11 出版日期:2017-12-05 发布日期:2017-12-05
  • 通讯作者: Chuan-Yu Zhang E-mail:zhangchuanyu10@cdut.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11404042 and 11604029), the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20135122120010), and the Open Research Fund of Computational Physics Key Laboratory of Sichuan Province, Yibin University (Grant No. JSWL2015KFZ02).

First-principles calculations of structure and elasticity of hydrous fayalite under high pressure

Chuan-Yu Zhang(张传瑜)1, Xu-Ben Wang(王绪本)1, Xiao-Feng Zhao(赵晓凤)1, Xing-Run Chen(陈星润)1, You Yu(虞游)2, Xiao-Feng Tian(田晓峰)3   

  1. 1. College of Geophysics, Chengdu University of Technology, Chengdu 610059, China;
    2. College of Optoelectronic Technology, Chengdu University of Information Technology, Chengdu 610225, China;
    3. College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610059, China
  • Received:2017-06-14 Revised:2017-09-11 Online:2017-12-05 Published:2017-12-05
  • Contact: Chuan-Yu Zhang E-mail:zhangchuanyu10@cdut.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11404042 and 11604029), the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20135122120010), and the Open Research Fund of Computational Physics Key Laboratory of Sichuan Province, Yibin University (Grant No. JSWL2015KFZ02).

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摘要： The structures, elasticities, sound velocities, and electronic properties of anhydrous and hydrous fayalite (Fe2SiO4 and Fe1.75H0.5SiO4) under high pressure have been investigated by means of the density functional theory within the generalized gradient approximation (GGA) with the on-site Coulomb energy being taken into account (GGA+U). The optimized results show that H atoms prefer to substitute Fe atoms in the Fe1 site. Compared with the anhydrous fayalite Fe2SiO4, the mass density, elastic moduli, and sound velocities of Fe1.75H0.5SiO4 slightly decrease. According to our data, adding 2.3 wt% water into fayalite leads to reductions of compressional and shear wave velocities (VP and VS) by 3.4%-7.5% and 0.3%-3.4% at pressures from 0 GPa to 25 GPa, respectively, which are basically in agreement with the 2%-5% reductions of sound velocity obtained by the experimental measurement in the low velocity zones (LVZ). Based on the electronic structure, the valence and conduction bands are slightly broader for hydrous fayalite. However, hydrous fayalite keeps the insulation characteristics under the pressures up to 30 GPa, which indicates that hydration has little effect on its electronic structure.

关键词: hydrous fayalite, first-principles theory, crystal structure, elasticity

Abstract: The structures, elasticities, sound velocities, and electronic properties of anhydrous and hydrous fayalite (Fe2SiO4 and Fe1.75H0.5SiO4) under high pressure have been investigated by means of the density functional theory within the generalized gradient approximation (GGA) with the on-site Coulomb energy being taken into account (GGA+U). The optimized results show that H atoms prefer to substitute Fe atoms in the Fe1 site. Compared with the anhydrous fayalite Fe2SiO4, the mass density, elastic moduli, and sound velocities of Fe1.75H0.5SiO4 slightly decrease. According to our data, adding 2.3 wt% water into fayalite leads to reductions of compressional and shear wave velocities (VP and VS) by 3.4%-7.5% and 0.3%-3.4% at pressures from 0 GPa to 25 GPa, respectively, which are basically in agreement with the 2%-5% reductions of sound velocity obtained by the experimental measurement in the low velocity zones (LVZ). Based on the electronic structure, the valence and conduction bands are slightly broader for hydrous fayalite. However, hydrous fayalite keeps the insulation characteristics under the pressures up to 30 GPa, which indicates that hydration has little effect on its electronic structure.

Key words: hydrous fayalite, first-principles theory, crystal structure, elasticity

中图分类号:  (Insulators)

  • 61.82.Ms
63.20.dk (First-principles theory) 61.50.Ah (Theory of crystal structure, crystal symmetry; calculations and modeling) 91.60.Ba (Elasticity, fracture, and flow)