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4시 20분부터 제1과학관 31214 e+강의실에서 다과를 준비하오니 많은 참석 부탁드립니다

아 래

제목: Hybrid Josephson Junctions of Various Nanostructures

연사: 도  용  주 교수님 (고려대학교)

일시: 2011년 5월 11(수) 오후4:30

장소: e+첨단강의실 (31214호실)

초록: Recent advances in nanofabrication techniques, however, have enabled the fabrication of hybrid quantum devices of superconductors and nanostructures (such as nanowires, carbon nanotube, and graphene), the Josephson coupling energy of which can be tuned electrically by the application of the gate voltage. We observed the macroscopic quantum tunnelling (MQT) of a Josephson phase particle, which exhibits a crossover from the classical to quantum regime, in a superconductor-graphene-superconductor (SGS) Josephson junction. Most importantly, the crossover temperature was controlled with the gate voltage, implying that the discrete energy level of a phase particle is also gate-tunable and a new class of quantum device such as a gate-tunable phase quantum bit (qubit) would be possible utilizing the MQT behaviour of the SGS junctions. We believe that our results demonstrate a powerful new approach in the controllability of macroscopic quantum states in a Josephson junction, and can be readily generalized for other nanostructures, including semiconductor nanowires and carbon nanotubes. Ultimately, this will be a key step toward developing a nanostructure-based superconducting qubits.