Density Functional Theory

Advances in Applications

Ponnadurai Ramasami

• Publisher: De Gruyter
• Year: 2018
• eBook ISBN: 9783110566956
• Edition: 1
• Topic: Scienze fisiche
• Subtopic: Chimica

DFT methods are widely used in a broad range of disciplines to investigate many body systems. This book provides an overview on contemporary applications of the Density Functional Theory in various fields as computational chemistry, physics or engineering.

Suman Chowdhury and Debnarayan Jana

1 Optical properties of monolayer BeC under an external electric field: A DFT approach

This article has previously been published in the journal Physical Sciences Reviews. Please cite as: Chowdhury, S., Jana, D. Optical properties of monolayer BeC under an external electric field: A DFT approach Physical Sciences Reviews [Online] 2018, 3. DOI: 10.1515/psr-2017-0162

Abstract: BeC, a two-dimensional hypercoordinated nanostructure carbon compound, has been the focus of the nanoworld because of its high value of dynamical stability, in-plane stiffness, carrier mobility and the existence of band gap. In this work, we have explored the electronic and the optical properties of this material under the influence of static external perpendicular electric field within the framework of density functional theory. Under the influence of a uniform electric field, the band gap changes within the meV range. The electron energy loss function study reveals that this material has optical band gaps which remain constant irrespective of the applied electric field strength. The optical property also exhibits interesting features when the applied field strength is within 0.4–0.5 V/Å. We have also tried to explain the optical data from the respective band structures and thus paving the way to understand qualitatively the signature of the optical anisotropy from the birefringence study.

Keywords: electronic properties, optical properties, density functional theory

1.1 Introduction

The era of two-dimensional (2D) materials has started through the experimental discovery of graphene in 2004 [1, 2, 3, 4, 5]. It has attracted the scientific community because of its unusual and exotic properties. For an example, the charge carriers in graphene move at a very high speed due to its linear dispersion relation at the $K$

point on the Brillouin zone (BZ). So, it is natural to think of using pure graphene in the electronic industry. But because of its zero band gap at the Fermi energy, its use in electronic industry as a switch is restricted. So, opening of band gap with suitable order of magnitude in graphene has been an important key issue in the study of 2D materials. Various possible ways have been predicted to open band gap in graphene: by B-N doping [6, 7, 8, 9], by chemical functionalization [10, 11, 12] and by applying strain [13]. Topological defects like Stone–Wales defects and local defects like voids can also alter the electronic structure of graphene significantly [14, 15, 16].

It is now clear that pristine graphene can no longer be used as a...

Table of contents

• Cover
• Title Page
• Copyright
• Contents
• Also of interest
• Preface
• List of Contributing authors
• 1 Optical properties of monolayer BeC under an external electric field: A DFT approach
• 2 Theoretical investigation of the derivatives of favipiravir (T-705) as potential drugs for Ebola virus
• 3 Potential thermally activated delayed fluorescence properties of a series of 2,3-dicyanopyrazine based compounds
• 4 γ-Al2O3:Ce3+Cu2+ as a phosphor material; DFT+U and experimental approach
• 5 A DFT perspective analysis of optical properties of defected germanene mono-layer
• 6 DFT studies on storage and adsorption capacities of gases on MOFs
• 7 Metastability of the boron-vacancy complex in silicon: Insights from hybrid functional calculations
• 8 Molecular structure and vibrational spectra of 2-(4-bromophenyl)-3-(4-hydroxyphenyl) 1,3-thiazolidin-4-one and its selenium analogue: Insights using HF and DFT methods
• 9 Complexes between core-modified porphyrins ZnP(X)4 (X = P and S) and small semiconductor nanoparticle Zn6S6: are they possible?
• 10 DFT computations on vibrational spectra: Scaling procedures to improve the wavenumbers
• 11 Substituent effects on linear and nonlinear optical properties of fluorescent (E)-2-(4-halophenyl)-7-arlstyrylimidazo[1,2-A] pyridine: spectroscopic and computational methods
• Index