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Majorana Zero Modes in Solid State Systems

dc.contributor.advisorDas Sarma, Sankaren_US
dc.contributor.authorHui, Hoi Yinen_US
dc.date.accessioned2015-06-26T05:32:29Z
dc.date.available2015-06-26T05:32:29Z
dc.date.issued2015en_US
dc.identifierhttps://doi.org/10.13016/M2X637
dc.identifier.urihttp://hdl.handle.net/1903/16589
dc.description.abstractMajorana zero modes are zero-energy excitations that are their own anti-particles, and obey non-Abelian statistics which could be harnessed for topological quantum computation. There are many theoretical proposals to realize them in solid state systems, but experimental realizations are confronted by a number of non-idealities. In this thesis, we theoretically investigate such complications, thereby suggesting improvement and directions that could be pursued. We first develop a theoretical framework to analyze the effect of ensemble-averaged disorder on the Majorana zero modes, generalizing the Eilenberger theory to handle 1D systems while retaining short-distance fluctuations. We then consider disordered topological insulator-based heterostructures, showing that extra subgap states are potentially induced, obscuring the density-of-states signature of the Majorana zero mode. We also analyze in depth the experimentally observed soft gap feature, suggesting that a cleaner interface in the semiconductor-based proposal can harden the gap. In view of some of the limitations of the proposals based on semiconductors or topological insulators, we look into a new class of systems in which a ferromagnetic atomic chain is put on the surface of a bulk spin-orbit-coupled superconductor. This system is analyzed in two limits, corresponding to weak or strong inter-atomic hopping on the chain. In each of these cases, the topological criteria are obtained. We also find that in the limit of strong chain-superconductor coupling, the length scales of the effective Hamiltonian of the chain are significantly suppressed, potentially explaining some of the recent observations in experiments.en_US
dc.language.isoenen_US
dc.titleMajorana Zero Modes in Solid State Systemsen_US
dc.typeDissertationen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.contributor.departmentPhysicsen_US
dc.subject.pqcontrolledPhysicsen_US
dc.subject.pquncontrolledDisorderen_US
dc.subject.pquncontrolledEilenbergeren_US
dc.subject.pquncontrolledMajoranaen_US
dc.subject.pquncontrolledTopological Insulatoren_US
dc.subject.pquncontrolledTopological Quantum Computationen_US
dc.subject.pquncontrolledTopological Superconductivityen_US


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