Giant spin splitting and $0-\pi$ Josephson transitions from the Edelstein effect in quantum spin-Hall insulators

Abstract

Hybrid structures of quantum spin-Hall insulators (QSHIs) and superconductors (Ss) present a unique opportunity to access dissipationless topological states of matter, which, however, is frequently hindered by the lack of control over the spin polarization in QSHIs. We propose a very efficient spin-polarization mechanism based on the magnetoelectric (Edelstein) effect in superconducting QSHI structures. It acts akin to the Zeeman splitting in an external magnetic field, but with an effective $g$-factor of order of 1000, resulting in an unprecedented spin-splitting effect. It allows a magnetic control of the QSHI/S hybrids without destroying superconductivity. As an example, we demonstrate a recurrent crossover from ${\Phi }_0$ - to ${\Phi }_0/2$ - periodic oscillations of the Josephson current in an rf superconducting quantum interference device (${\Phi }_0=h/2e$ is the magnetic flux quantum). The predicted period halving is a striking manifestation of $0-\pi$ Josephson transitions with a superharmonic $\pi$-periodic current-phase relationship at the transition. Such controllable $0-\pi$ transitions may offer new perspectives for dissipationless spintronics and engineering flux qubits.

5 pages, 4 figures

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Cited by in corpus (8)

• Transport in two-dimensional topological materials: recent developments in experiment and theory
• Nonlocal Thermoelectricity in a S-TI-S Junction in Contact with a N-Metal Probe: Evidence for Helical Edge States
• Thermodynamics in topological Josephson junctions
• Planar Josephson Hall effect in topological Josephson junctions
• Chiral current-phase relation of topological Josephson junctions: A signature of the $4\pi$-periodic Josephson effect
• Spin and orbital Edelstein effect in spin-orbit coupled noncentrosymmetric superconductor
• Probing the magnetoelectric effect in noncentrosymmetric superconductors by equal-spin Andreev tunneling
• Tuning Majorana zero modes with temperature in $\pi$-phase Josephson junctions