Prof. Klaus Ensslin

ETH, Zurich

Electron transport through graphene quantum structures

Abstract:

Graphene quantum dots have been prepared by exfoliation, electron-beam lithography and plasma etching. Coulomb bockade has been demonstrated and the charge configuration of dot states and coupling strength to source and drain contacts was tuned by graphene in-plane gates. Also spin states in graphene quantum dots have been detected and the spin filling sequence for a series of orbital states has been identified. Double dots have been fabricated in graphene and the excited states spectrum has been investigated. Using scanning gate techniques charge localization has been characterized in the quantum dot as well as in the neighboring constrictions. Recently we managed to measure the quantum capacitance of bulk graphene, investigate chemically modified graphene as well as detect current rectification in three terminal graphene junctions. In this talk I will give an overview over experiments on graphene nanostructures with a focus on the nature of quantum confinement and the options provided by multi-terminal quantum devices. Recent experiment on coherent phonon emission in quantum dots will also be discussed.