Detecting Topological Superconductivity with ${\phi }_0$ Josephson Junctions

Abstract

The interplay of superconductivity, magnetic fields, and spin-orbit interaction lies at the heart of topological superconductivity. Remarkably, the recent experimental discovery of ${\phi }_0$ Josephson junctions by Szombati et al., Nat. Phys. 12, 568 (2016), characterized by a finite phase offset in the supercurrent, require the same ingredients as topological superconductors, which suggests a profound connection between these two distinct phenomena. Here, we theoretically show that a quantum dot ${\phi }_0$ Josephson junction can serve as a new qualitative indicator for topological superconductivity: Microscopically, we find that the phase shift in a junction of $s-$wave superconductors is due to the spin-orbit induced mixing of singly occupied states on the qantum dot, while for a topological superconductor junction it is due to singlet-triplet mixing. Because of this important difference, when the spin-orbit vector of the quantum dot and the external Zeeman field are orthogonal, the $s$-wave superconductors form a $\pi$ Josephson junction while the topological superconductors have a finite offset ${\phi }_0$ by which topological superconductivity can be distinguished from conventional superconductivity. Our prediction can be immediately tested in nanowire systems currently used for Majorana fermion experiments and thus offers a new and realistic approach for detecting topological bound states.

References in corpus (22)

• Non-Abelian Anyons and Topological Quantum Computation
• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices
• Majorana Fermions and a Topological Phase Transition in Semiconductor-Superconductor Heterostructures
• Observation of Majorana Fermions in Ferromagnetic Atomic Chains on a Superconductor
• Supercurrent reversal in quantum dots
• Direct coupling between magnetism and superconducting current in Josephson Phi junction
• Gapless Andreev bound states in the quantum spin Hall insulator HgTe
• Josephson ${\phi }_0$-junction in nanowire quantum dots
• Direct Measurement of the Spin-Orbit Interaction in a Two-Electron InAs Nanowire Quantum Dot
• Anomalous Josephson effect induced by spin-orbit interaction and Zeeman effect in semiconductor nanowires
• Edge-mode Superconductivity in a Two Dimensional Topological Insulator
• Anomalous Josephson Current in Junctions with Spin-Polarizing Quantum Point Contacts
• Josephson radiation from gapless Andreev bound states in HgTe-based topological junctions
• Experimental evidence of a ϕ Josephson junction
• Hard superconducting gap in InSb nanowires
• Universal Quantum Computation with Hybrid Spin-Majorana Qubits
• Spin Orbit coupling and Anomalous Josephson effect in Nanowires
• Fermionic and Majorana Bound States in Hybrid Nanowires with Non-Uniform Spin-Orbit Interaction
• Anomalous Josephson effect in semiconducting nanowires as a signature of the topologically nontrivial phase
• Josephson current through a quantum dot with spin-orbit coupling
• φ-State and Inverted Fraunhofer Pattern in Nonaligned Josephson Junctions

Cited by in corpus (23)

• The Josephson diode effect in supercurrent interferometers
• Spin-dependent coupling between quantum dots and topological quantum wires
• Topological Phase Detection in Rashba Nanowires with a Quantum Dot
• Spontaneous supercurrent and $\varphi$0 phase shift parallel to magnetized topological insulator interfaces
• Parity protected superconducting diode effect in topological Josephson junctions
• Quantum-Dot Parity Effects in Trivial and Topological Josephson Junctions
• Anomalous Josephson Effect in S/SO/F/S heterostructures
• Boundary spin polarization as robust signature of topological phase transition in Majorana nanowires
• Long-range Kitaev Chains via Planar Josephson Junctions
• Enhancement of the thermoelectric effect due to the Majorana zero modes coupled to one quantum-dot system
• Coupled superconducting spin qubits with spin-orbit interaction
• Geometric Josephson effects in chiral topological nanowires
• From perfect to imperfect poor man's Majoranas in minimal Kitaev chains
• Josephson effect in junctions of conventional and topological superconductors
• Supercurrent parity-meter in a nanowire Cooper-pair transistor
• Dissipationless Nonlinearity in Quantum Material Josephson Diodes
• Electrically modulated SQUID with single Josephson junction coupled by a time-reversal breaking Weyl semimetal thin film
• ${\theta }_0$ thermal Josephson junction
• Impact of junction length on supercurrent resilience against magnetic field in InSb-Al nanowire Josephson junctions
• Critical current for an insulating regime of an underdamped current-biased topological Josephson junction
• Superconducting spin properties of Majorana nanowires and the associated superconducting anomalous Hall effect
• Anomalous Andreev interferometer: Study of an anomalous Josephson junction coupled to a normal wire
• Originality of resonance and locking phenomena in SFS ${\phi }_0$ Josephson junction