Ab initio calculations of structural, electronic, optical and thermodynamic properties of alkaline earth tellurides Ba_xSr_1鈭扻Te

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• 作者：B. Bahloul ; A. Bentabet ; L. Amirouche ; Y. Bouhadda ; S. Bounab ; B. Deghfel ; N. Fenineche
• 关键词：A. Semiconductors ; C. Ab initio calculations ; D. Thermodynamic properties
• 刊名：Journal of Physics and Chemistry of Solids
• 出版年：March, 2014
• 年：2014
• 卷：75
• 期：3
• 页码：307-314
• 全文大小：775 K

文摘

Structural, electronic and thermodynamic properties of SrTe and BaTe compounds and their ternary mixed crystals Ba_xSr_1鈭抶Te in the rock-salt structure have been studied with density functional theory (DFT), whereas the optical properties have been obtained by using empirical methods such as the modified Moss relation. The exchange-correlation potential was calculated using the generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) and the local density approximation (LDA) of Teter-Pade (TP). In the present work, we used the virtual-crystal approximation (VCA) to study the effect of composition (x). The calculated lattice parameters at equilibrium volume and the bulk modulus for x=0 and x=1 are in good agreement with the literature data. Furthermore, the Ba_xSr_1鈭抶Te alloys are found to be an indirect band gap semiconductor. In addition, we have also predicted the heat capacities (C_V), the entropy(S), the internal energy (U) and the Helmholtz free energy (F) of the parent compounds SrTe and BaTe.