Pressure Effects on the Band Structure of BCC Lithium with Substitutional Hydrogen Defect
-
摘要: 利用第一原理的平面波-赝势密度泛函方法,研究了零温下体心立方(bcc)金属锂由于氢的替位掺杂和外界压力的改变所引起的电子结构变化。结果表明:掺杂体系仍然呈金属性,但是由于氢原子俘获了一个金属自由电子,具有了离子属性,使得费米面以下出现了孤立能带和带隙,最低金属价带偏离了自由电子带,形成鞍型带底,其它价带和导带均出现不同程度的简并解除和带型畸变。在压力的作用下,带隙加宽,费米面下的孤立带趋向于一条直线,成为一条能级。Abstract: The pressure effects on the band structure of bcc lithium with substitutional hydrogen defect are studied by using ab initio pseudopotential-plane wave method at 0 K temperature. Even though the impurity hydrogen atom localizes a free electron in the sea of metallic valence electrons, the doped system still acts as metal, but an isolated band and a band gap appear under Fermi level, the lowest metallic band is distorted at Gamma point, and elsewhere in other conduction and valence bands. When pressures applied on the system, the band gap is widened and the isolated band tends to be stretched horizontally into a line, just like an energy level.
-
Key words:
- ab initio /
- band structure /
- pressure effect /
- impurity /
- lithium
-
Wigner E, Seitz F. On the Constitution of Metallic Sodium [J]. Phys Rev, 1933, 43: 804-810. Seitz F. The Theoretical Constitution of Metallic Lithium [J]. Phys Rev, 1935, 47: 400-412. Callaway J, Zou X, Bagayoko D. Total Energy of Metallic Lithium [J]. Phys Rev B, 1983, 27: 631-635. Dacorogna M M, Cohen M L. First-Principles Study of the Structural Properties of Alkali Metals [J]. Phys Rev B, 1986, 34: 4996-5002. Dugourd V B, Bordas C. Electronic Properties and Geometric Structures of Li4H and Li9H from Optical Absorption Spectra [J]. J Chem Phys, 1995, 102: 2727-2736. Ray A K, Hira A S. Many-Body Perturbation Theory Applied to Hydrogen Interaction with Lithium Clusters [J]. Phys Rev B, 1988, 37: 9943-9950. Li Y C, Guo Y, Tan F L, et al. Equation of State for Al-Li Alloy [J]. Chinese Journal of High Pressure Physics, 2003, 17(2): 81-87. (in Chinese) 李永池, 郭扬, 谭福利, 等. 铝锂合金材料状态方程的研究 [J]. 高压物理学报, 2003, 17(2): 81-87. Ma Y M, Cui T, He W J, et al. Pressure and Temperature Effects on the System of Lithium Doped in Solid D2 [J]. Chinese Journal of High Pressure Physics, 2003, 17(2): 88-94. (in Chinese) 马琰铭, 崔田, 何文炯, 等. 压力和温度对固氘掺锂体系的影响 [J]. 高压物理学报, 2003, 17(2): 88-94. Hamann D R, Schlter M, Chiang C. Norm-Conserving Pseudopotentials [J]. Phys Rev Lett, 1979, 43: 1494-1497. Ceperley D M, Alder B J. Ground State of the Electron Gas by a Stochastic Method [J]. Phys Rev Lett, 1980, 45: 566-569. Perdew J P, Zunger A. Self-Interaction Correction to Density-Functional Approximations for Many-Electron Systems [J]. Phys Rev B, 1981, 23: 5048-5079. Monkhorst H J, Pack J D. Special Points for Brillouin-Zone Integrations [J]. Phys Rev B, 1976, 13: 5188-5192. Fischer T H, Almlf J. General Methods for Geometry and Wave Function Optimization [J]. J Phys Chem, 1992, 96: 9768-9774. Segall A M D, Lindan P L D, Probert M J, et al. First-Principles Simulation: Ideas, Illustrations and the CASTEP Code [J]. J Phys: Conden Matter, 2002, 14: 2717-2743.
点击查看大图
计量
- 文章访问数: 8040
- HTML全文浏览量: 296
- PDF下载量: 761