Investigation of geometry, energetics and electronic structure of twisted bilayer graphene

buir.advisorGülseren, Oğuz
dc.contributor.authorAmine, Nouha
dc.date.accessioned2024-08-19T11:17:31Z
dc.date.available2024-08-19T11:17:31Z
dc.date.copyright2024-08
dc.date.issued2024-08
dc.date.submitted2024-08-07
dc.descriptionCataloged from PDF version of article.
dc.descriptionThesis (Master's): Bilkent University, Department of Physics, İhsan Doğramacı Bilkent University, 2024.
dc.descriptionIncludes bibliographical references (leaves 85-88).
dc.description.abstractTwisted bilayer graphene (TBG) manifests unique electronic properties that hold substantial potential for advancements in nanotechnology, material science, and quantum computing. In this thesis, critical insights into the fundamental charac-teristics of TBG are uncovered through an in-depth exploration of its geometric configurations, interlayer interactions, and electronic properties. We begin our investigation with a thorough analysis of the geometrical properties of the twisted bilayer graphene. By plotting the unit cell size against twist angles, we uncover distinct patterns and symmetries that emerge at different angles, offering insights into the fundamental structural properties that influence the material’s behavior. Following this, we examine the interlayer energies using both Lennard-Jones (LJ) and Kolmogorov-Crespi (KC) potentials. Our analysis of local stacking configurations reveals that the interlayer energy remains invariant due to the averaging contributions from AA and AB regions. We then analyze the band structures across various twist angles using tight-binding calculations, computing parameters such as Fermi velocity and effective mass of the electrons. We observe the emergence of flat bands at ”magic angles” and other unique band structures at specific twist angles, highlighting the complex electronic behavior of TBG.
dc.description.provenanceSubmitted by Betül Özen (ozen@bilkent.edu.tr) on 2024-08-19T11:17:31Z No. of bitstreams: 1 B162583.pdf: 16882048 bytes, checksum: 9ac9e4f4571db0948c1c795e2c83b3e6 (MD5)en
dc.description.provenanceMade available in DSpace on 2024-08-19T11:17:31Z (GMT). No. of bitstreams: 1 B162583.pdf: 16882048 bytes, checksum: 9ac9e4f4571db0948c1c795e2c83b3e6 (MD5) Previous issue date: 2024-08en
dc.description.statementofresponsibilityby Nouha Amine
dc.format.extentxvii 88 leaves : color illustrations, charts ; 30 cm.
dc.identifier.itemidB162583
dc.identifier.urihttps://hdl.handle.net/11693/115748
dc.language.isoEnglish
dc.rightsinfo:eu-repo/semantics/openAccess
dc.subjectTwisted bilayer graphene
dc.subjectMoir´e pattern
dc.subjectLennard-jones potential
dc.subjectKolmogorov-crespi potential
dc.subjectLocal stackings
dc.subjectTight-binding
dc.subjectBand structure
dc.titleInvestigation of geometry, energetics and electronic structure of twisted bilayer graphene
dc.title.alternativeBükülmüş iki katmanlı grafenin geometresinin, enerjitik ve elektronik yapısının incelenmesi
dc.typeThesis
thesis.degree.disciplinePhysics
thesis.degree.grantorBilkent University
thesis.degree.levelMaster's
thesis.degree.nameMS (Master of Science)

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