Doctor of Philosophy,
University of Sargodha, 2019
Ph.D. Thesis Title
First Principles Investigation of Electronic, Optical and Transport Properties of Pyrochlore Oxides
Condensed Matter Physics (Electronic Structure Calculation): In condensed matter physics, I do study on Electronic Structure, Elastic properties, optical and thermoelectric properties of the solid materials in the light of Density Functional Theory (DFT). It may be mentioned that with the knowledge of band structure of a material, the understanding of various properties of materials has been increased in the past few decades. Starting with atomic number only, the electronic structure calculation can be done and based on the information one can engineer to modify the crystal structure and further can determine the total energies of all the possible crystal structures. Thus the most stable structure can be determined.
In the second part, I study on the elastic properties of the materials. It is of particular interest as they determine the mechanical stability of the materials. Elastic properties of a solid are important because of they relate to various fundamental solid state properties. Therefore, it will be desirable if before carrying out expensive and tedious time consuming process of experiments to determine electronic band structure, density of states and elastic properties and one can use computational tools for theoretical calculation to understand these parameters and hence save both the time and resources for technology development with better-designed experiments.
DFT is commonly used to calculate the electronic structure of simple and complex systems containing many atoms such as large molecules or solids. It is based on electron density rather than on the wave function and treated both exchange and correlation but approximately. In this method, many body problems of interacting electrons and nuclei are mapped to a series of one-electron equations which is called Kohn-Sham (KS) equations. For the solution of the KS equations, several methods have been developed with the Linearized Augmented Plane Wave (LAPW). Based on this, a computer code WIEN2K is used to solve the KS equations and thus obtain the crystal properties on atomic scale.u.