高等学校化学学报

高等学校化学学报 ›› 2003, Vol. 24 ›› Issue (5): 863.

• 论文 • 上一篇    下一篇

TiC固体的相稳定性和高压相变的密度泛函研究

章永凡, 李俊篯, 丁开宁, 陈文凯, 周立新   

  1. 福州大学化学系, 福州 350002
  • 收稿日期:2002-04-09 出版日期:2003-05-24 发布日期:2003-05-24
  • 通讯作者: 李俊辘(1942年出生),男,教授,博士生导师,从事固体电子结构和化学键的理论研究.E-mail:quant@fzu.edu.cn E-mail:quant@fzu.edu.cn
  • 基金资助:

    国家自然科学基金(批准号:20273013);福建省教育厅基金(批准号:K02012);福州大学科技发展基金(批准号:XKJ0105);福建省青年科技人才创新项目基金(批准号:2001J018)

A Density Functional Study on the Phase Stability and Phase Transitions at High Pressure for TiC Solid

ZHANG Yong-Fan, LI Jun-Qian, DING Kai-Ning, CHEN Wen-Kai, ZHOU Li-Xin   

  1. Department of Chemistry, Fuzhou University, Fuzhou 350002, China
  • Received:2002-04-09 Online:2003-05-24 Published:2003-05-24

PDF (PC)

被引次数

5

摘要： 采用基于第一性原理的密度泛函方法对TiC固体的NaCl,WC和CsCl三种相的电子结构进行了研究,结果表明,在零压力下相稳定次序为NaCl>WC>CsCl,该顺序可用费米能级附近电子态的大小加以解释,当增加外压力时,随着单胞体积的减小,CsCl相逐渐成为稳定相,在外压约为475.9GPa时,NaCl相将向CsCl相转变,而CsCl相转变为WC相要求的外压较高.此外,还进一步探讨了压力对三种相的能带结构、化学键以及电荷密度的影响.

关键词: 过渡金属碳化物, 能带结构, 化学键, 相稳定性, 密度泛函理论

Abstract: Using the density function theory method based on the first principle, the electronic structures of TiCsolid with the NaCl, WC and CsCl phases have been investigated. The calculated results indicate that, at the zero pressure, the order of relative stability for the three phases is NaCl phase>WCphase> CsCl phase, and this order can be explained by comparing the electronic states near the Fermi level. As the pressure increases, the CsCl phase is to be stable and the structural phase transitions from NaCl phase to CsCl phase occurs at about 475. 9 GPa. The transition from CsCl phase to WCphase needs more higher pressure. Furthermore, the pressure-induced influences on the band structures, chemical bonding and charge densities of the three phases are also discussed.

Key words: Transition metal carbides, Energy band structures, Chemical bonding, Phase stability, Densi- ty functional theory

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