Electronic structure and physical properties of Alkali Metal Oxides and Chalcogenides and Magnetism induced by SP Dopants

Abstract

Density functional theory (DFT) based electronic structure calculations have been widely used to study, and has successfully described various properties of many condensed matter systems. The thesis is an attempt to understand the series of undoped and doped compounds using density functional theory. In this connection a series of systems has been chosen and a detailed study has been made to see salient features and trends in the calculated ground state properties, electronic structure, high pressure study and magnetism. The present work involves systems with many atoms per cell the tight-binding linear muffin-tin orbital (TB-LMTO) methods turn out to be a good choice. The thesis presented here deals with theoretical calculations of the electronic structure properties for a series of alkali metal oxides M2O and chalcogenides M2A and magnetism induced by non-magnetic sp (Group - IV(C, Si, Ge, Sn, Pb), V and VII (F, Cl, Br, I)) dopants in M2O compounds. The purpose of this study is to gain further knowledge on the electronic structure and ground-state properties of these binary compounds and try to provide reference for future experimental as well as theoretical studies related to these compounds. Secondly, the goal of the thesis is to learn the effect of non-magnetic sp dopants in alkali metal oxides. The main objective of the thesis in this regard, is to demonstrate the increased applicability and versatility of theoretical calculations as a complement to experiments. In this thesis an attempt has been made to describe the state of the art of studies in the field of first-principle calculations and the study of properties and prospects for the application of a new class of magnetic compounds obtained from nonmagnetic compounds doped with nonmagnetic sp dopants. Trends in the ground state properties, spinpolarization energy and magnetic moment are discussed. Finally summary and conclusion of the present investigations along with future scope of work is presented in this thesis. newline