Effects of Na, Mg, and Al substitution on the electronic, optical, lattice dynamical, and thermodynamic properties of semiboride Be2B
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- 作者：M. T. Kadri ; H. Belkhir and S. Ouchene
- 刊名：physica status solidi (b)
- 出版年：2016
- 出版时间：August 2016
- 年：2016
- 卷：253
- 期：8
- 页码：1596-1606
- 全文大小：1372K
- ISSN：1521-3951
文摘
The structural, electronic, and optical properties of Be2B and its ternary compounds XBeB (X = Al, Na, and Mg) have been calculated using the full-potential linearized augmented plane wave (FP_LAPW) method, which is based on the first-principles method with the generalized gradient approximation (GGA) and the local density approximation (LDA). While, the lattice dynamical and thermodynamic properties were performed using the density functional perturbation theory (DFPT). The calculated lattice constants are in good agreement with the available theoretical and experimental values. The partial density of states (PDOS), and phonon dispersion curves have been obtained and compared with previous works. An accurate calculation of the dielectric function, refractive index, reflectivity, optical conductivity, absorption spectra, extinction coefficient, and energy-loss spectrum were performed. The first time calculated optical properties suggest that AlBeB can be used as possible shields for UV radiations. The phonon dispersion results of the investigated compounds confirm the dynamical stability of both structures Be2B and AlBeB. However the soft modes are observed for both compounds MgBeB and NaBeB, indicating their dynamical instability. Finally, the first time calculated thermodynamic properties showed clearly the thermodynamic instability of NaBeB compound.