Stabilization and control of Majorana bound states with elongated skyrmions

Güngördü, Utkan; Sandhoefner, Shane; Kovalev, Alexey A.

doi:10.1103/physrevb.97.115136

Cited by 45 publications

(36 citation statements)

References 61 publications

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“…We note that although B y is negligibly small and both B x and B z exhibit an oscillatory behavior, the x-component of the fringing field largely dominates. The resulting fringing field is therefore quite different from the helical-like and skyrmion-like textures considered in previous investigations of MBS [37,38]. Therefore, it is somehow surprising that in spite of having a non-helical character, the textures illustrated in Fig.…”

Section: Theoretical Modelcontrasting

confidence: 58%

Electrical Control of Majorana Bound States Using Magnetic Stripes

Mohanta

Zhou

et al. 2019

Phys. Rev. Applied

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A hybrid semiconductor-superconductor nanowire on the top of a magnetic film in the stripe phase experiences a magnetic texture from the underlying fringing fields. The Zeeman interaction with the highly inhomogeneous magnetic textures generates a large synthetic spin-orbit coupling. We show that this platform can support the formation of Majorana bound states (MBS) localized at the ends of the nanowire. The transition to the topological superconducting phase not only depends on the nanowire parameters and stripe size but also on the relative orientation of the stripes with respect to the nanowire axis. Topological phase transitions with the corresponding emergence or destruction of MBS can be induced by reorienting the stripes or shifting their position, which can be achieved by passing a charge current through the magnetic film or by applying electrically-controlled strain to it. The proposed platform removes the need for external magnetic fields and offers a non-invasive electrical tuning of MBS with the perturbation (current or strain) acting only on thee magnetic film.

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Section: Theoretical Modelcontrasting

confidence: 58%

Electrical Control of Majorana Bound States Using Magnetic Stripes

Mohanta

Zhou

et al. 2019

Phys. Rev. Applied

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“…For skyrmions on s-wave and p-wave superconductors, Yu-Shiba-Rusinov-like bound states have been considered [42,43]. With regard to Majorana physics, effective p-wave phases with chiral edge modes have been predicted [44,45], whereas localized MBS may emerge in elongated skyrmions [46] which resemble nanowires. For more complicated skyrmion textures, Yang et al [47] have derived the criterion that a pair of MBS can form for skyrmions of even winding number, with one state being localized at the skyrmion core and the partner state at the outer rim of the skyrmion.…”

Section: Introductionmentioning

confidence: 99%

Majorana bound states in magnetic skyrmions imposed onto a superconductor

2019

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We consider a superconducting film exchange-coupled to a close-by chiral magnetic layer and study how magnetic skyrmions can induce the formation of Majorana bound states (MBS) in the superconductor. Inspired by a proposal by Yang et al. [Phys. Rev. B 93, 224505 (2016)], which suggested MBS in skyrmions of even winding number, we explore whether such skyrmions could result from a merger of ordinary skyrmions. We conclude that the formation of higher-winding skyrmions is not realistic in chiral magnets. Subsequently, we present a possibility to obtain MBS from realistic skyrmions of winding number one, if a skyrmion-vortex pair is formed instead of a bare skyrmion. Specifically, we show that MBS are supported in a pair of a circular skyrmion and a vortex which both have a winding number of one. We back up our analytical prediction with results from numerical diagonalization and obtain the spatial profile of the MBS. In light of recent experimental progress on the manipulation of skyrmions, such systems are promising candidates to achieve direct spatial control of MBS. arXiv:1904.04177v2 [cond-mat.supr-con]

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“…For example, state-of-the art fabrication of superconducting junctions with topological insulators [38] would support fabrication of similar X-shaped junctions. With the progress in tunable magnetic textures used to modify proximity-induced superconductivity [23,27,[39][40][41][42][43][44][45][46][47][48][49], X-shaped junctions could be considered with a reduced role of an applied magnetic field.…”

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confidence: 99%

Phase Control of Majorana Bound States in a Topological X Junction

et al. 2020

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Topological superconductivity supports exotic Majorana bound states (MBS) which are chargeless zeroenergy emergent quasiparticles. With their non-Abelian exchange statistics and fractionalization of a single electron stored nonlocally as a spatially separated MBS, they are particularly suitable for implementing fault-tolerant topological quantum computing. While the main efforts to realize MBS have focused on one-dimensional systems, the onset of topological superconductivity requires delicate parameter tuning and geometric constraints pose significant challenges for their control and demonstration of non-Abelian statistics. To overcome these challenges, building on recent experimental advances in planar Josephson junctions (JJs), we propose a MBS platform of X-shaped JJs. This versatile implementation reveals how external flux control of the superconducting phase difference can generate and manipulate multiple MBS pairs to probe non-Abelian statistics. The underlying topological superconductivity exists over a large parameter space, consistent with materials used in our fabrication of such X junctions, as an important step towards scalable topological quantum computing. arXiv:1909.05386v1 [cond-mat.mes-hall]

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Stabilization and control of Majorana bound states with elongated skyrmions

Cited by 45 publications

References 61 publications

Electrical Control of Majorana Bound States Using Magnetic Stripes

Electrical Control of Majorana Bound States Using Magnetic Stripes

Majorana bound states in magnetic skyrmions imposed onto a superconductor

Phase Control of Majorana Bound States in a Topological X Junction

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