Control of Edge Currents at a Ferromagnet - Triplet Superconductor Interface by Multiple Helical Majorana Modes

Abstract

We study the spin and charge currents flowing at the interface of an itinerant ferromagnet with a topological spin-triplet superconductor having different number of time-reversal-invariant Majorana helical modes. Depending on the number of helical modes, the capacity of carrying spin and charge currents is shown to be directly related to the amplitude and orientation of the ferromagnetic magnetization with respect to the superconducting $\vec{d}$-vector. Differently from the one-helical mode spin-triplet superconductor, we find that the presence of a finite amount of electronic hybridization with the two pairs of Majorana helical modes leads to nonvanishing charge current independently of the ferromagnetic exchange. The competition between the two pairs of Majorana helical modes remarkably yields a spin-current response that is almost constant in the range of weak to intermediate ferromagnetism. The behavior of the spin current is tightly linked to the direction of the spin-polarization in the ferromagnet and tends to be flatten for a magnetization that is coplanar to the spin-triplet $\vec{d}$-vector independently of the number of helical modes.

14 pages, 13 figures

References in corpus (22)

• Topological Insulators with Inversion Symmetry
• Classification of topological insulators and superconductors in three spatial dimensions
• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Superconducting Spintronics
• Time Reversal Polarization and a Z_2 Adiabatic Spin Pump
• Topological Defects and Gapless Modes in Insulators and Superconductors
• Quantum Spin Hall Effect and Topologically Invariant Chern Numbers
• Topological Phases of Noncentrosymmetric Superconductors: Edge States, Majorana Fermions, and the Non-Abelian Statistics
• Chiral P-Wave Order in Sr_2RuO_4
• A General Theorem Relating the Bulk Topological Number to Edge States in Two-dimensional Insulators
• Topological properties of spin-triplet superconductors and the Fermi surface topology in the normal state
• Manifestation of the odd-frequency spin-triplet pairing state in diffusive ferromagnet / superconductor junctions
• Majorana bound states and non-local spin correlations in a quantum wire on an unconventional superconductor
• Topological aspects of quantum spin Hall effect in graphene: Z${}_2$ topological order and spin Chern number
• Interplay of ferromagnetism and triplet superconductivity in a Josephson junction
• Andreev spectroscopy and surface density of states for a three-dimensional time-reversal invariant topological superconductor
• Theory of Josephson effect in unconventional superconducting junctions with diffusive barriers
• Origin and control of spin currents in a magnetic triplet Josephson junction
• Topological p+ip superconductivity in doped graphene-like single-sheet materials BC${}_3$
• Zeeman field induced topological phase transitions in triplet superconductors
• Ferromagnetic SrRuO3 thin-film deposition on a spin-triplet superconductor Sr2RuO4 with highly conducting interface
• Helical Majorana surface states of strongly disordered topological superconductors with time-reversal symmetry

Cited by in corpus (7)

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• Spin-triplet superconductor$-$quantum anomalous Hall insulator$-$spin-triplet superconductor Josephson junctions: $0$-$\pi$ transition, ${\varphi }_0$ phase and switch effects
• Direct and inverse superspin Hall effect in two-dimensional systems: Electrical detection of spin supercurrents
• Inverse Proximity Effects at Spin-Triplet Superconductor-Ferromagnet Interface
• Topological signatures of the coexistence of antiferromagnetism and odd-parity spin-triplet superconductivity
• Controllable enhancement of $p$-wave superconductivity via magnetic coupling to a conventional superconductor