Tight binding model of ab stacked bilayer graphene

AB stacked Bilayer graphene is a material of huge scientific interest due to the promise of superior electronic properties even when compared to monolayer graphene due to more ?? orbital overlaps in the x-y plane. In this research the Nearest Neighbor Tight-Binding (NNTB) model of AB stacked bilayer...

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Main Author:	Poobalan, Prashanth
Format:	Thesis
Language:	English
Published:	2022
Subjects:	TK Electrical engineering Electronics Nuclear engineering
Online Access:	http://eprints.utm.my/102696/1/PrashanthPoobalanMSKE2022.pdf.pdf
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id	my-utm-ep.102696
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spelling	my-utm-ep.1026962023-09-18T03:59:57Z Tight binding model of ab stacked bilayer graphene 2022 Poobalan, Prashanth TK Electrical engineering. Electronics Nuclear engineering AB stacked Bilayer graphene is a material of huge scientific interest due to the promise of superior electronic properties even when compared to monolayer graphene due to more ?? orbital overlaps in the x-y plane. In this research the Nearest Neighbor Tight-Binding (NNTB) model of AB stacked bilayer graphene will be developed. Using this NNTB approximation, a numerical analysis simulator that uses the Non- Equilibrium Greens Function (NEGF) equations to describe the quantum transport of the electrons in the bilayer graphene crystal is built using MATLAB. From this numerical analysis simulation, various metrics of interest such as the E-K dispersion relation, density of states (DOS) and the transmission coefficients will be obtained for each of the specified lattice width and length. Electronic properties of two variants of the bilayer graphene are investigated in this simulation, which are the zigzag edge and the armchair edge types. The program constructs a fitting device Hamiltonian for the NEFG equation from the specified type, width, and length. The NEGF simulation obtains the solution for the dispersion relation, DOS and transmission coefficient for each of the eigen energies iteratively until the solution converges to a minimum error threshold value. The DOS simulation showed there is a huge concentration of quantum states in the mid-band for the zigzag edge, and for the armchair edge the number of states is the largest at the 1st quartile-band and 3rd quartile-band region. Transmission coefficient of both zigzag and armchair edges show similar distribution throughout the energy spectrum; however, the coefficients magnitude of the zigzag edge is larger. Dispersion relation of zigzag edge showed no bandgap, though the armchair edge showed an alternating trend of semiconducting (with bandgap) from the 3n-1 and 3n series and metallic (no bandgap) for 3n+1 series in agreement with contemporary research. 2022 Thesis http://eprints.utm.my/102696/ http://eprints.utm.my/102696/1/PrashanthPoobalanMSKE2022.pdf.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:149756 masters Universiti Teknologi Malaysia Faculty of Engineering - School of Electrical Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TK Electrical engineering Electronics Nuclear engineering
spellingShingle	TK Electrical engineering Electronics Nuclear engineering Poobalan, Prashanth Tight binding model of ab stacked bilayer graphene
description	AB stacked Bilayer graphene is a material of huge scientific interest due to the promise of superior electronic properties even when compared to monolayer graphene due to more ?? orbital overlaps in the x-y plane. In this research the Nearest Neighbor Tight-Binding (NNTB) model of AB stacked bilayer graphene will be developed. Using this NNTB approximation, a numerical analysis simulator that uses the Non- Equilibrium Greens Function (NEGF) equations to describe the quantum transport of the electrons in the bilayer graphene crystal is built using MATLAB. From this numerical analysis simulation, various metrics of interest such as the E-K dispersion relation, density of states (DOS) and the transmission coefficients will be obtained for each of the specified lattice width and length. Electronic properties of two variants of the bilayer graphene are investigated in this simulation, which are the zigzag edge and the armchair edge types. The program constructs a fitting device Hamiltonian for the NEFG equation from the specified type, width, and length. The NEGF simulation obtains the solution for the dispersion relation, DOS and transmission coefficient for each of the eigen energies iteratively until the solution converges to a minimum error threshold value. The DOS simulation showed there is a huge concentration of quantum states in the mid-band for the zigzag edge, and for the armchair edge the number of states is the largest at the 1st quartile-band and 3rd quartile-band region. Transmission coefficient of both zigzag and armchair edges show similar distribution throughout the energy spectrum; however, the coefficients magnitude of the zigzag edge is larger. Dispersion relation of zigzag edge showed no bandgap, though the armchair edge showed an alternating trend of semiconducting (with bandgap) from the 3n-1 and 3n series and metallic (no bandgap) for 3n+1 series in agreement with contemporary research.
format	Thesis
qualification_level	Master's degree
author	Poobalan, Prashanth
author_facet	Poobalan, Prashanth
author_sort	Poobalan, Prashanth
title	Tight binding model of ab stacked bilayer graphene
title_short	Tight binding model of ab stacked bilayer graphene
title_full	Tight binding model of ab stacked bilayer graphene
title_fullStr	Tight binding model of ab stacked bilayer graphene
title_full_unstemmed	Tight binding model of ab stacked bilayer graphene
title_sort	tight binding model of ab stacked bilayer graphene
granting_institution	Universiti Teknologi Malaysia
granting_department	Faculty of Engineering - School of Electrical Engineering
publishDate	2022
url	http://eprints.utm.my/102696/1/PrashanthPoobalanMSKE2022.pdf.pdf
_version_	1783729211543912448

Tight binding model of ab stacked bilayer graphene

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