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dc.creatorBebek, Bahadir
dc.date.accessioned2016-06-27T19:49:56Z
dc.date.available2016-06-27T19:49:56Z
dc.date.created2016-05
dc.date.issued2016-05
dc.date.submittedMay 2016
dc.identifier.urihttp://hdl.handle.net/2346/67069
dc.description.abstractThe interactions between heat flow and defects is universally believed to involve the scattering of thermal phonons by the defect. This process is assumed to conserve momentum and sometimes to be elastic as well. But the atomistic nature of the processes involved is never described. This Thesis deals with the theoretical description of the interactions between a heat front and well-defined defects using entirely first-principles tools: density-functional theory for the electronic states and ab-initio molecular-dynamics (MD) simulations for the nuclear dynamics. No empirical parameters are used and no assumption about the nature of the interactions is made. The host material is a Si nanowire containing a thin layer of atoms X = Ge or C, and the Si|X interface is the defect. The theoretical developments include the construction of a strictly microcanonical periodic ‘cluster’ in which heat flow initially in just one direction, MD simulations performed without thermostat and with unprecedented temperature control, and the analysis of the energy distribution vs time which distinguishes between one- and two-phonon processes. The results of the MD simulations show that the dynamic properties of the defect play the central role in phonon-defect interactions and that no scattering process of any kind occurs. The interactions include only the coupling between delocalized (host-material) and localized (defect-related) oscillators. These interactions are temperature dependent: a given defect is predicted to behave differently in different temperature ranges. The consequences of these findings are discussed.
dc.format.mimetypeapplication/pdf
dc.language.isoeng
dc.subjectHeat flow, phonons, Defects, Semiconductor, interface, Molecular Dynamics
dc.titleHeat flow in Si nanowires containing delta-layers
dc.typeThesis
dc.date.updated2016-06-27T19:49:56Z
dc.type.materialtext
thesis.degree.nameDoctor of Philosophy
thesis.degree.levelDoctoral
thesis.degree.disciplinePhysics
thesis.degree.grantorTexas Tech University
thesis.degree.departmentPhysics
dc.contributor.committeeMemberSanati, Mahdi
dc.contributor.committeeMemberBernussi, Ayrton
dc.contributor.committeeMemberPeralta, Luis Grave de
dc.contributor.committeeChairEstreicher, Stefan K.
dc.rights.availabilityUnrestricted.
dc.creator.orcid0000-0002-0412-4559


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