期刊
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
卷 70, 期 1, 页码 64-71出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.jpcs.2008.09.004
关键词
Inorganic compounds; Ab initio calculations; Crystal structure; Electronic structure; Thermodynamic properties
First principles calculations have been performed with the purpose to understand the comparative peculiarities of the structural, electronic properties and stability for all phases formed in the tungsten-carbon system: hexagonal and cubic mono-carbides WC and four polymorphs (alpha, beta, gamma and epsilon) of semi-carbide W2C. All calculations were performed by means of the full-potential linearized augmented plane wave method (FLAPW). The generalized gradient approximation (GGA) in the Perdew-Burke-Ernzerhof (PBE) formalism was used for the exchange and correlation energy functional. The geometries of all WC and W2C phases were optimized and their structural parameters and theoretical density were established, Besides, we have evaluated the formation energies (E-form) of all the tungsten carbides. Based on our estimations we can arrange all investigated W-C phases depending on their stability in the following sequence: h-WC>epsilon-W2C>beta-W2C>gamma-W2C>alpha-W2C>c-WC. Here three carbides (h-WC, epsilon-W2C and beta-W2C) are stable (E-form<0), gamma-W2C belongs to metastable systems (E-form similar to 0), whereas alpha-W2C and c-WC appear to be unstable (E-form > 0). Moreover, band structures, total and partial densities of states were obtained and analyzed systematically for all W-C phases in comparison with other available theoretical and experimental data. (C) 2008 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据