Effects of the Vacancy Point-Defect on Electronic Structure and Optical Properties of Diamond under High Pressure
-
摘要: 基于密度泛函理论框架下的平面波超软赝势方法,分别计算了255 GPa压力下金刚石理想晶体以及含空位点缺陷晶体时的电子结构和光学性质。结果表明,在255 GPa的冲击压力下,冲击诱导的空位点缺陷的存在使得在金刚石的能隙中出现了缺陷电子态;在可见光区390~570 nm范围内产生了一定的光吸收,金刚石在该波段的光学透明性降低,但在可见光区的高波段金刚石却仍保持透明(其吸收系数仍为零);空位点缺陷的存在对反射谱和能量损失谱的影响相似,谱主峰均向短波方向微移,且峰值强度都略有降低。Abstract: By ultra-soft pseudo-potential approach of the plane wave based on the density-functional theory, the electronic structures and optical properties of diamond without and with vacancy point-defects were calculated at 255 GPa. The calculated results show that: at a shock pressure of 255 GPa, shock-induced vacancy point-defects in diamond crystal cause defective states within the band gap, and the optical absorption induced by the vacancy point-defects appears in the visible-light region of ~390-570 nm, and there is the transparency loss of diamond in that region. However, in the visible-light region of ~570-780 nm diamond remains transparent (its optical-absorption coefficient is still zero). Effects of shock-induced vacancy-defects on reflectivity and loss-function spectrums are similar: main-spectral peak move slightly toward short-wave region, and their intensity decreases to a small degree.
-
Key words:
- high pressure /
- vacancy point-defect /
- diamond /
- first principles /
- electronic structure /
- optical properties
-
Li J, Zhou X M, Li J B. A time-resolved single-pass technique for measuring optical absorption coefficent of window materials under 100 GPa shock pressures [J]. Rev Sci Instrum, 2008, 79(12): 123107. Zhou X M, Wang X S, Li S N, et al. Optical transparency of z-cut LiF, Al2O3, LiTaO3 single crystals under strong shock compression [J]. Acta Phys Sin, 2007, 56(8): 4965-4970. (in Chinese) 周显明, 汪小松, 李赛男, 等. 强冲击压缩下LiF, Al3O2和LiTaO3单晶的透光性 [J]. 物理学报, 2007, 56(8): 4965-4970. Yoo C S, Holmes N C, Ross M, et al. Shock temperatures and melting of iron at Earth core conditions [J]. Phys Rev Lett, 1993, 70(25): 3931-3934. Dolan D H, Ao T. Cubic zirconia as a dynamic compression window [J]. Appl Phys Lett, 2008, 93(2): 021908. Stevens G D, Veeser L R, Rigg P A. Suitability of magnesium oxide as a VISAR window [J]. AIP Conf Proc, 2005, 845: 1353-1356. Nellis W J. Systematics of compression of hard materials [J]. J Phys: Conf Ser, 2008, 121: 062005. Guo J L, Liu F S, Hao G Y, et al. Temperature measurement for the interface of the dense bulk iron/sapphire window under shock compression [J]. Chinese Journal of High Pressure Physics, 2008, 22(4): 414-418. (in Chinese) 郭锦良, 刘福生, 郝高宇, 等. 块状密实铁/蓝宝石界面的冲击温度测量 [J]. 高压物理学报, 2008, 22(4): 414-418. Meyers M A. Dynamic Behavior of Materials [M]. New York: John Willey Sons, 1994: 413-420. He L, Tang M J, Fang Y, et al. Origin of the change of the electrical and optical properties in shocked Al2O3 and prediction of an increase in electrical conductivity in MgSiO3 at pressure-temperature conditions of Earth's D layer [J]. Europhys Lett, 2008, 83(3): 39001. He X, He L, Tang M J, et al. Effects of the vacancy point-defect on electronic structure and optical properties of LiF under high pressure: A first principles investigation [J]. Acta Phys Sin, 2011, 60(2): 026012. (in Chinese) 何旭, 何林, 唐明杰, 等. 第一性原理研究空位点缺陷对高压下LiF的电子结构和光学性质的影响 [J]. 物理学报, 2011, 60(2): 026012. He L, Tang M J, Yin J, et al. Effects of the vacancy point-defect on the refractive index and equation of state (EOS) of LiF at high pressure: A first principles investigation [J]. Phys B: Condensed Matter, 2012, 407(4): 694-697. Segall M D, Lindan P J D, Probert M J. First-principles simulation: Ideas, illustrations and the CASTEP code [J]. J Phys: Condens Matter, 2002, 14(11): 2717. Payne M C, Teter M P, Allan D C. Iterative minimization techniques for ab initio total-energy calculations: Molecular dynamics and conjugate giadients [J]. Rev Mod Phys, 1992, 64(4): 1045-1097. Perdew J P, Zunger A. Self-interaction correction to density-function approximation for many-electron systems [J]. Phys Rev B, 1981, 23 (10): 5048-5079. Perdew J P, Burke K, Ernzerhof M. Generalized gradient approximation made simple [J]. Phys Rev Lett, 1996, 77(18): 3865-3868. Fischer T H, Almlof J. General methods for geometry and wave function optimization [J]. J Phys Chem, 1992, 96(24): 9768-9774. Kittel C. Quantum Theory of Solids [M]. 2nd ed. New York: John Willey Sons, 1987: 14. Holm B, Ahuja R, Yourdshahyan Y. Elastic and optical properties of -and -Al2O3 [J]. Phys Rev B, 1999, 59(20): 12777-12787. Wu J, Walukiewicz W, Shan W. Temperature dependence of the fundamental band Gap of InN [J]. J Appl Phys, 2003, 94(7): 4457-4460.
点击查看大图
计量
- 文章访问数: 6296
- HTML全文浏览量: 341
- PDF下载量: 416