Date of Award

2025-08-01

Degree Name

Doctor of Philosophy

Department

Computational Science

Advisor(s)

Tunna Baruah

Abstract

Density Functional Theory (DFT) has established itself as a practical and versatile method for efficiently studying the properties of materials of solids and molecules. Despite being exact in principle, in practice, DFT calculations rely on an approximation for the exchange-correlation energy functional of the electron density. This results in an erroneous interaction of the electron with itself, known as the self-interaction error (SIE). It arises from the fact that the exchange self-interaction does not exactly cancel out the Coulomb self-interaction. Due to this error, the approximate one-electron potential decays exponentially in the asymptotic region rather than exhibiting the correct ?1 r decay.This results in excessive delocalization of electrondensity, resulting in the delocalization error, which affects electronic, magnetic, and other properties. In this regard, we applied two -one-electron self-interaction correction (SIC) schemes to understand the effects of SIE on chemical barrier heights, exchange coupling constants, and polarizability in molecular systems. Our results showed that removal of self-interaction error improves the description of barrier heights, exchange coupling constants, and polarizability of conjugated molecular chains, and in all cases the recently developed local-scaling SIC method of Zope et al performs significantly better than the better-known Perdew-Zunger SIC method. The latter part of the thesis is dedicated to the exploration of 2D materials, which possess unique electrical, optical, and magnetic proper-ties that have captured significant interest in materials science and condensed matter physics. We focus on a few layered 2D materials that have the potential to drive new advances in spintronics and data storage devices. One of the most intriguing aspects is that the unique properties of such 2D materials can be manipulated using external agents, such as light, electric fields, pressure, doping, and vacancies. This approach opens up new avenues for advancement in the development of next-generation spintronics devices and high-capacity data storage technologies. In this thesis, we present our studies on the magnetic, electronic, and vibrational properties of 2D magnetic layered materials under the influence of external pressure and radiation.

Language

en

Provenance

Received from ProQuest

File Size

205 p.

File Format

application/pdf

Rights Holder

Prakash Mishra

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