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Refraction of Dirac Fermions across Molecular Graphene Junctions

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Název: Refraction of Dirac Fermions across Molecular Graphene Junctions
Autoři: Yankelevich, Beatriz, Stanford University, Program in Engineering Physics, Manoharan, Hari, Dionne, Jennifer
Informace o vydavateli: Stanford Digital Repository, 2025.
Rok vydání: 2025
Témata: condensed matter physics, refraction, tachyonic behavior, individual atomic manipulation, graphene, Veselago lens, Dirac fermions, scanning tunneling microscopy, molecular graphene
Popis: Graphene has been a subject of great interest in condensed matter physics due to its exotic topological properties. We have used an STM capable of individual atomic manipulation to engineer molecular graphene nanostructures which host relativistic massless Dirac fermions and constitute a fully-tunable electronic system. Motivated by this light-like behavior, our ultimate goal is to create a Veselago lens out of flakes of doped molecular graphene. This work explores the refraction of Dirac fermions across various types of molecular graphene junctions, including neutral-p, neutral-n, n-n, and neutral graphene - 2 dimensional electron system junctions. Principle to our analysis is a new technique combining the traditional quasi-particle interference method used in scanning tunneling microscopy with individual atomic manipulation, which allows us to investigate the scattering of electron wave functions in 2D systems with great precision. Finally, we also explore the possibility of ’tachyonic’ behavior of Dirac fermions as they refract across junctions from areas with higher to lower group velocities. We find significant evidence of refraction of Dirac fermions across various junctions, as well as propose a theoretical explanation for the angles of refraction based off of band structure. We also find evidence of ’tachyonic behavior’ in Dirac fermion refraction.
Druh dokumentu: Thesis
DOI: 10.25740/jk427px7127
Rights: CC BY NC
Přístupové číslo: edsair.doi...........321484d79930ace27c192381100d4bee
Databáze: OpenAIRE
Popis
Abstrakt:Graphene has been a subject of great interest in condensed matter physics due to its exotic topological properties. We have used an STM capable of individual atomic manipulation to engineer molecular graphene nanostructures which host relativistic massless Dirac fermions and constitute a fully-tunable electronic system. Motivated by this light-like behavior, our ultimate goal is to create a Veselago lens out of flakes of doped molecular graphene. This work explores the refraction of Dirac fermions across various types of molecular graphene junctions, including neutral-p, neutral-n, n-n, and neutral graphene - 2 dimensional electron system junctions. Principle to our analysis is a new technique combining the traditional quasi-particle interference method used in scanning tunneling microscopy with individual atomic manipulation, which allows us to investigate the scattering of electron wave functions in 2D systems with great precision. Finally, we also explore the possibility of ’tachyonic’ behavior of Dirac fermions as they refract across junctions from areas with higher to lower group velocities. We find significant evidence of refraction of Dirac fermions across various junctions, as well as propose a theoretical explanation for the angles of refraction based off of band structure. We also find evidence of ’tachyonic behavior’ in Dirac fermion refraction.
DOI:10.25740/jk427px7127