弹道狄拉克半金属约瑟夫森结中塞曼效应诱导的0-π跃迁

Zeeman-Effect-Induced 0-π Transitions in Ballistic Dirac Semimetal Josephson Junctions.

作者信息

Li Chuan, de Ronde Bob, de Boer Jorrit, Ridderbos Joost, Zwanenburg Floris, Huang Yingkai, Golubov Alexander, Brinkman Alexander

机构信息

MESA+ Institute for Nanotechnology, University of Twente, Enschede 7500 AE, The Netherlands.

Van der Waals-Zeeman Institute, IoP, University of Amsterdam, Amsterdam 1098 XH, The Netherlands.

出版信息

Phys Rev Lett. 2019 Jul 12;123(2):026802. doi: 10.1103/PhysRevLett.123.026802.

DOI:10.1103/PhysRevLett.123.026802

PMID:31386548

Abstract

One of the consequences of Cooper pairs having a finite momentum in the interlayer of a Josephson junction is π-junction behavior. The finite momentum can either be due to an exchange field in ferromagnetic Josephson junctions, or due to the Zeeman effect. Here, we report the observation of Zeeman-effect-induced 0-π transitions in Bi_{1-x}Sb_{x}, three-dimensional Dirac semimetal-based Josephson junctions. The large in-plane g factor allows tuning of the Josephson junctions from 0 to π regimes. This is revealed by measuring a π phase shift in the current-phase relation measured with an asymmetric superconducting quantum interference device (SQUID). Additionally, we directly measure a nonsinusoidal current-phase relation in the asymmetric SQUID, consistent with models for ballistic Josephson transport.

摘要

库珀对在约瑟夫森结的层间具有有限动量的一个后果是π结行为。有限动量要么是由于铁磁约瑟夫森结中的交换场，要么是由于塞曼效应。在此，我们报告了在基于三维狄拉克半金属Bi_{1-x}Sb_{x}的约瑟夫森结中塞曼效应诱导的0 - π转变的观测结果。大的面内g因子使得能够将约瑟夫森结从0态调节到π态。这通过使用非对称超导量子干涉器件（SQUID）测量电流 - 相位关系中的π相移得以揭示。此外，我们直接测量了非对称SQUID中的非正弦电流 - 相位关系，这与弹道约瑟夫森输运模型一致。