Single electron pumping in graphene based nanostructures

• Applicant: Dr. Bernd Kästner
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2010 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 172516151

In graphene single electron devices the spin decoherence times of the electrons are not intrinsically limited by a strong spin orbit coupling or by hyperfine interaction like e.g. in Ga(Al)As. Therefore graphene is discussed as a promising material for quantum information processing using spin quantum bits (qubits). One building block of every spin quantum computer is an on-demand source of single electrons allowing to inject or extract a single electron into or out of the quantum computation device. In this project graphene based single electron pumps will be realized, experimentally investigated, and their suitability for application as a clocked on-demand sources of single electrons will be tested. Two different approaches will be explored: hybrid superconductor-graphene turnstiles and non-adiabatic single electron pumps based on gated graphene nanoribbons. The dynamics of capture and ejection of individual electrons will be scrutinized by single shot measurements in combination with single charge detection. Comparison of the pumped current to theoretical models will allow to pinpoint effects related to the special electronic band structure in graphene (Klein paradoxon). The results of this project will define a path towards high fidelity graphene single electron pumps with various applications in quantum electronics. They will further allow a deep insight in the electronic transport dynamics of graphene nanostructures under the influence of time dependent electrical fields.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1459: Graphen
• Participating Person: Privatdozent Dr. Hans-Werner Schumacher