Two-Dimensional Topological Superconductivity with Antiferromagnetic Insulators

Lado, José L.; Sigrist, Manfred

doi:10.1103/physrevlett.121.037002

Cited by 32 publications

(20 citation statements)

References 64 publications

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“…Indeed, it has been shown [127] that SWCB 4 is equivalent to a SSC 4 texture for |B z | < 2|M ⊥ |. This allows us to establish a connection to prior works [85,[194][195][196][197] which have focused on the emergence of chiral topological superconducting phases in other magnetic platforms. The above criterion also implies that, for |B z | > 2|M ⊥ |, SWCB 4 transforms into a ferromagnetic profile, which is expected to render the system trivial.…”

Section: Swcb4 Texture -Majorana Bidirectional/chiral Edge Modessupporting

confidence: 62%

Topological Superconductivity Induced by Magnetic Texture Crystals

Steffensen,

Christensen,

Andersen

et al. 2020

Preprint

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We present an in-depth classification of the topological phases and Majorana fermion (MF) excitations that arise from the bulk interplay between unconventional multiband spin-singlet superconductivity and various magnetic textures. We focus on magnetic texture crystals with a periodicallyrepeating primitive cell of the helix, whirl, and skyrmion types. Our analysis is relevant for a wide range of layered materials and hybrid devices, and accounts for both strong and weak, as well as crystalline topological phases. We identify a multitude of accessible topological phases which harbor flat, uni-or bi-directional, (quasi-)helical, or chiral MF edge modes. This rich variety of MFs originates from the interplay between topological phases with gapped and nodal bulk energy spectra, with the resulting types of spectra and MFs controlled by the size of the pairing and magnetic gaps.

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Section: Swcb4 Texture -Majorana Bidirectional/chiral Edge Modessupporting

confidence: 62%

Topological Superconductivity Induced by Magnetic Texture Crystals

Steffensen,

Christensen,

Andersen

et al. 2020

Preprint

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“…1,25 Finally, by inducing a superconducting order parameter the system becomes gapped and Majorana zero modes may emerge. 12 We also note that a similar phenomenon was predicted to occur at the interface between superconductors and antiferromagnetic insulators, 26 suggesting that the role of the quantum Hall state in graphene is just to induce high correlations in the flat-band zeroth Landau level. 24 Mean-field simulations of such graphene/superconductor junctions corroborated this proposal for hosting Majorana zero modes, and an ad hoc phenomenological model for the edge states was proposed from numerical band diagram calculations.…”

Section: Introductionsupporting

confidence: 66%

Effective model for Majorana modes in graphene

2019

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It was recently proposed that the interface between a graphene nanoribbon in the canted antiferromagnetic quantum Hall state and a s-wave superconductor may present topological superconductivity, resulting in the appearance of Majorana zero modes. 1 However, a description of the low-energy physics in terms of experimentally controllable parameters was still missing. Starting from a mean-field continuum model for graphene in proximity to a superconductor, we derive the low-energy effective Hamiltonian describing the interface of this heterojunction from first principles. A comparison between tight-binding simulations and analytical calculations with effective masses suggests that normal reflections at the interface must be considered in order to fully describe the low-energy physics.

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“…The spectrum is obtained by BdG transformation. While both the superconductor and the antiferromagnet have an excitation gap, we find at the interface a zero-energy eigenvalue with an eigenoperator [2,[42][43][44],…”

Section: (D))mentioning

confidence: 74%

Solitonic in-gap modes in a superconductor-quantum antiferromagnet interface

Lado

Sigrist

2020

Phys. Rev. Research

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Bound states at interfaces between superconductors and other materials are a powerful tool to characterize the nature of the involved systems, and to engineer elusive quantum excitations. In-gap excitations of conventional s-wave superconductors occur, for instance, at magnetic impurities with net magnetic moment breaking time-reversal symmetry. Here we show that interfaces between a superconductor and a quantum antiferromagnet can host robust in-gap excitations, without breaking time-reversal symmetry. We illustrate this phenomenon in a one-dimensional model system with an interface between a conventional s-wave superconductor and a one-dimensional Mott insulator described by a standard Hubbard model. This genuine many-body problem is solved exactly by employing a combination of kernel polynomial and tensor network techniques. We unveil the nature of such zero modes by showing that they can be adiabatically connected to solitonic solutions between a superconductor and a classical antiferromagnet. Our results put forward a new class of in-gap excitations between superconductors and a disordered quantum spin phase can be relevant for a wider range of heterostructures.

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Two-Dimensional Topological Superconductivity with Antiferromagnetic Insulators

Cited by 32 publications

References 64 publications

Topological Superconductivity Induced by Magnetic Texture Crystals

Topological Superconductivity Induced by Magnetic Texture Crystals

Effective model for Majorana modes in graphene

Solitonic in-gap modes in a superconductor-quantum antiferromagnet interface

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