عنوان البحث(Papers / Research Title)
Semi-empirical LUC-INDO calculations for the effect of pressure on the electronic structure of diamond
الناشر \ المحرر \ الكاتب (Author / Editor / Publisher)
احمد محمود عبد اللطيف الخفاجي
Citation Information
احمد,محمود,عبد,اللطيف,الخفاجي ,Semi-empirical LUC-INDO calculations for the effect of pressure on the electronic structure of diamond , Time 5/9/2011 1:46:11 PM : كلية العلوم
وصف الابستركت (Abstract)
A self-consistent formalism has been used to study the electronic properties of diamond
الوصف الكامل (Full Abstract)
A self-consistent LUC (Large Unit Cell) formalism on the basis of semi-empirical INDO (Intermediate Neglect of Differential Overlap) Hamiltonians has been used to study the electronic properties of diamond and to investigate the pressure dependence of these properties. The calculated properties are in good agreement with the experiments except the conduction band width. The increase of pressure on diamond is predicted to cause the following effects; an increase of the valence and conduction band widths with a decrease of the direct band gap, an increase of the electronic occupation probability for the p orbital with a decrease of this probability for the s orbital, and a decrease of the x-ray scattering factor.
Introduction
The band theory of solids is usually employed to consider characteristics of the electronic structure of a crystal which are associated with the potential periodicity and the corresponding electronic-state delocalization over the crystal, namely, the electronic energy bands, effective masses, etc. The electronic and structural properties of solids are a subject of considerable interest in both fundamental and applied physics. Even though remarkable progress has been achieved in a wide variety of problems, determination of the electronic and structural properties remains a theoretical challenge. Up to present, band structure calculations are still subject to immense numerical efforts. Among the methods used in this field is the self-consistent LUC-INDO method in the linear combination of atomic orbitals (LCAO) approximation. This method, which had been already successfully employed for a long time in molecular theory, has gained wide acceptance in calculations of the electronic structure of crystals. The LUC-INDO method compares well in accuracy with other approaches while being at the same time, the best starting approximation to take into account electronic correlations [1]. This method has been used in the present work to study the electronic properties of diamond and to investigate the effect of pressure on these properties.
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