Cooper pair splitting in a two-dimensional electron gas II: Spin-resolved measurements

ORAL

Abstract

Information about the spin of electrons forming a Cooper pair, can be accessed by coupling spin-polarized quantum dots via a superconductor. Here, we study Cooper pair splitting (CPS) in a semiconductor two-dimensional electron gas, where two quantum dots are coupled via extended Andreev bound states. By applying an external magnetic field, the spin degeneracy of the quantum dot orbitals is lifted, allowing us to use them as bipolar spin filters. The specific spin involved in either elastic co-tunnelling (ECT) or CPS can then be resolved. With the magnetic field aligned along the spin-orbit field, we show that only equal-spin ECT and opposite-spin CPS is allowed to take place. However, upon applying the field perpendicular to the spin-orbit field, ECT and CPS currents arise for all spin combinations. Notably by rotating between these angles, we smoothly transition from fully singlet CPS to having an equal singlet and triplet CPS component.

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Presenters

  • Sebastiaan ten Haaf

    • Delft University of Technology

Authors

  • Sebastiaan ten Haaf

    • Delft University of Technology

  • Qingzhen Wang

    • Delft University of Technology

  • Ivan Kulesh

    • QuTech (Delft University of Technology)
    • Delft University of Technology

  • Candice Thomas

    • Purdue University
    • Department of Physics and Astronomy, Purdue University
    • Department of Physics and Astronomy, Purdue University,
    • Department of Physics and Astronomy and Birck Nanotechnology Center, Purdue University

  • Michael J Manfra

    • Purdue University, Microsoft Quantum Purdue
    • Purdue University
    • Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA; Microsoft Quantum Lab, Purdue University, West Lafayette, IN, USA
    • Physics and Astronomy, Purdue University
    • Department of Physics and Astronomy, Birck Nanotechnology Center, School of Electrical and Computer Engineering and Microsoft Quantum Lab West Lafayette, Purdue University
    • Department of Physics and Astronomy and Nanotechnology Center Purdue University, Microsoft Quantum Lab West Lafayette
    • Department of Physics and Astronomy, Birck Nanotechnology Center, School of Materials Engineering and School of Electrical and Computer Engineering, Purdue University

  • Di Xiao

    • Department of Physics and Astronomy, Purdue University
    • Purdue University

  • Srijit Goswami

    • QuTech (Delft University of Technology)
    • Delft University of Technology