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TT: Fachverband Tiefe Temperaturen
TT 41: Quantum Transport and Quantum Hall Effects II (joint session HL/TT)
TT 41.2: Vortrag
Mittwoch, 29. März 2023, 15:15–15:30, JAN 0027
Spin valves based on bilayer graphene quantum point contacts — •Eike Icking1,2, Christian Volk1,2, Christopher Schattauer3, Luca Banszerus1,2, Kenji Watanabe4, Takashi Taniguchi5, Florian Libisch3, Bernd Beschoten1, and Christoph Stampfer1,2 — 1RWTH Aachen University, Germany — 2Forschungszentrum Jülich, Germany — 3TU Vienna, Austria — 4Research Center for Functional Material, Japan — 5International Center for Materials Nanoarchitectonics, Japan
Bernal bilayer graphene (BLG) is a unique material as it allows opening and electrostatically tuning a sizeable band gap by applying a perpendicular electric field. Recently, charge carriers have been confined successfully in one dimension to form quantum point contacts (QPC) based on split gates separated by a channel of a few hundred nanometers. Moreover, spin-polarized quantum transport through such structures has been demonstrated up to 6 e2/h using a high in-plane magnetic field. The threshold magnetic field at which the lowest modes become spin-polarized depends on the subband spacing and thus on the width of the split gate channel. In this work, we combine two QPCs of different geometric widths, resulting in different threshold magnetic fields, to spin-polarize the first QPC and use it as a filter for the second QPC. In particular, we report on a spin-valve achieving spin-polarized channels with a total conductance of up to 10 e2/h.