Periodic Magnetoconductance oscillation in hybrid Nb-2DEG-Nb ballistic Josephson junctions

ORAL

Abstract

The principle of quantum transport in Nb-In0.75Ga0.25As-Nb Josephson junctions is the phase coherent Andreev reflections at the interfaces of the Nb and 2DEG in In0.75Ga0.25As, where the microscopic phase of the quasiparticles wavefunction in In0.75Ga0.25As and the macroscopic phase of the superconducting order parameter, are combined [1]. The conductance in this system is influenced by several kinds of interference effects. For instance, the conductance oscillates in a step- or sinusoidal- manner when the hybrid junctions are placed in a magnetic field which gives rise to Aharonov-Bohm type effect observation even in such a simply connected system.
Here, we report the first experimental observation of periodic conductance oscillation in ballistic Nb-In0.75Ga0.25As 2DEG-Nb junctions in the low magnetic field. We demonstrate that the dI/dV (B) has a maximum close to zero field which drops in a step-like manner when the field is increased. When the field is reversely swept, a hysteresis is observed which is accompanied by oscillation of dI/dV in a sinusoidal manner with a periodicity of ~15 mT at and below T= 320 mK.
[1] K. Delfanazari, et al., Adv. Mater. 29, 1701836 (2017).

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Presenters

  • Kaveh Delfanazari

    University of Cambridge

Authors

  • Kaveh Delfanazari

    University of Cambridge

  • R. Puddy

    University of Cambridge

  • P. Ma

    University of Cambridge

  • T. Yi

    University of Cambridge

  • M. Cao

    University of Cambridge

  • Y. Gul

    University College London

  • I. Farrer

    Department of Electronic and Electrical Engineering, University of Sheffield, University of Sheffield

  • D. Ritchie

    University of Cambridge

  • H. Joyce

    University of Cambridge

  • M. Kelly

    University of Cambridge

  • C. Smith

    University of Cambridge