Please use this identifier to cite or link to this item: https://hdl.handle.net/11147/7673
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dc.contributor.advisorÇakır, Özgür
dc.contributor.authorCanbolat, Ahmet Utku-
dc.date.accessioned2020-02-07T12:10:14Z
dc.date.available2020-02-07T12:10:14Z
dc.date.issued2019-07en_US
dc.identifier.citationCanbolat, A. U. (2019). RKKY interaction and its control in graphene and related materials. Unpublished master's thesis, İzmir Institute of Technology, İzmir, Turkeyen_US
dc.identifier.urihttps://hdl.handle.net/11147/7673
dc.descriptionThesis (Master)--Izmir Institute of Technology, Physics, Izmir, 2019en_US
dc.descriptionIncludes bibliographical references (leaves: 58-61)en_US
dc.descriptionText in English; Abstract: Turkish and Englishen_US
dc.description.abstractGraphene got dramatic attention and lead the two-dimensional material physics after its first successful synthesis in 2004. Its unique electronic properties contain great potential for both scientific and technological applications. RKKY (Ruderman-Kittel-Kasuya Yosida) is an indirect exchange interaction mediated by conduction electrons. In graphene, the interaction strength decay as 1/R³ where R is the distance between the magnetic moments. In the first part of this work, we calculated that applying circular potential on a graphene sheet forms quasi-bound states in the potential region. Via these states, the RKKY interaction is enhanced between magnetic moments on the edge of the potential well. This can be thought of an electronic analog of the Purcell effect. We showed that the interaction strength is even more enhanced if the Fermi level is in resonance with the energies of the quasi-bound states. In the second part, we considered zigzag edged hexagonal nanoflakes. It is known that zigzag edged flakes have zero-energy edge-states. It is also known that the states with closer energies contribute more to RKKY interaction. Thus, we calculated that there is an enhancement between these edge-states. In the third part, we investigated the behavior of RKKY interaction for two dimensional materials with quartic dispersion. An energy dispersion is said to be quartic if it is of the form E = α(k² - kc² )². Here, α and kc are material dependent constants. There are many materials exhibiting the quartic dispersion such as nitrogene, phosphorene, and arsenene. These materials are also sharing two-dimensional hexagonal lattice structure with graphene. What makes quartic dispersion special is that it has van-Hove singularity in its density of states near the band-edge. RKKY interaction is sensitive to the density of states because it depends on the number of electrons contributing spin exchange. Thus, the larger the number of electrons, the stronger the coupling. In this part, we tuned the Fermi level so that it lies on the DOS singularity and then we calculated the interaction strength as a function of R. We found a slowly decaying RKKY interaction for quartic dispersion. If the energy dispersion is pure quartic (i.e. E = ak4), we found the interaction strength depends on 1/(kf R) instead of 1/R which makes the RKKY interaction long range for arbitrarily small Fermi level.en_US
dc.description.sponsorshipTUBITAK (115F408)en_US
dc.format.extentxi, 70 leavesen_US
dc.language.isoenen_US
dc.publisherIzmir Institute of Technologyen_US
dc.rightsinfo:eu-repo/semantics/openAccessen_US
dc.subjectGrapheneen_US
dc.subjectRKKY interactionsen_US
dc.subjectFermi levelen_US
dc.subjectQuartic dispersionen_US
dc.titleRKKY interaction and its control in graphene and related materialsen_US
dc.title.alternativeGrafen ve benzeri malzemelerde RKKY etkileşimi ve kontrolüen_US
dc.typeMaster Thesisen_US
dc.institutionauthorCanbolat, Ahmet Utku-
dc.departmentThesis (Master)--İzmir Institute of Technology, Physicsen_US
dc.relation.tubitakinfo:eu-repo/grantAgreement/TUBITAK/MFAG/115F408
dc.relation.publicationcategoryTezen_US
item.openairetypeMaster Thesis-
item.openairecristypehttp://purl.org/coar/resource_type/c_18cf-
item.fulltextWith Fulltext-
item.languageiso639-1en-
item.cerifentitytypePublications-
item.grantfulltextopen-
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