Effective model for Majorana modes in graphene

Manesco, Antonio L. R.; Weber, G.; Rodrigues, Durval

doi:10.1103/physrevb.100.125411

Cited by 11 publications

(10 citation statements)

References 37 publications

(77 reference statements)

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“…Recent experimental works [15][16][17] motivate the combination of quantum Hall effect and superconducting order in graphene as a platform for Majorana zero modes [32]. Our results cover two different situations that prevent the existence of a non-trivial topological phase: (i) the strong intervalley scattering caused by disorder closes the topological gap; (ii) Fermi level mismatch promotes the population of undesired edge states along the NS interface [32,33]. Therefore, fabrication of high-quality graphene/superconductor heterostructures is necessary, for example, using van der Waals materials such as NbSe 2 [28].…”

Section: Experimental Relevancementioning

confidence: 54%

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Mechanisms of Andreev reflection in quantum Hall graphene

Manesco¹,

Flór²,

Liu³

et al. 2021

Preprint

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We perform realistic simulations of a hybrid superconductor-graphene device in the quantum Hall regime to indentify the origin of downstream resistance oscillations in a recent experiment [Zhao et. al. Nature Physics 16, (2020)]. A comparison between the simulations and the experimental data suggests that disorderinduced intervalley scattering at the normal-superconductor (NS) interface can be the dominant cause of oscillations. We also show conductance oscillations due to additional edge states on clean interfaces with Fermi level mismatch. However, the regular pattern as a function of external parameters is not visible in the presence of disorder. Our work provides a way to qualitatively probe the quality of NS interfaces on multiterminal quantum Hall devices.

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Section: Experimental Relevancementioning

confidence: 54%

“…We also simplify the problem by taking µ to be constant over the entire system. We now compute the effective hamiltonian using first order in perturbation theory [32,33,36]. The perturbation is…”

Section: B Low-energy Model Derivationmentioning

confidence: 99%

Mechanisms of Andreev reflection in quantum Hall graphene

Manesco¹,

Flór²,

Liu³

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…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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“…By inducing superconductivity in two dimensional systems in the quantum anomalous Hall (QAH) phase, the chiral topological superconductor with Bogolyubov-de Gennes (BdG) Chern number being nonzero could be engineered [15][16][17][18]. One of the most in- * Corresponding author:luoma@gpnu.edu.cn tensely studied systems is the graphene/superconductor [19][20][21][22][23][24] heterostructure duo to multiple superiority about the electronic and mechanic properties of graphene [25]. The magnetic exchange field in graphene could be obtained by doping or proximity to ferromagnetic substrate.…”

Section: Introductionmentioning

confidence: 99%

Chiral Majorana Fermions in two dimensional square lattice antiferromagnet with proximity-induced superconductivity

Luo¹

2022

Preprint

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Proximity-induced superconductivity in two dimensional square lattice antiferromagnet with spinorbit coupling and nonsymmorphic symmetry could induce topological superconductor phase with chiral Majorana edge states. The tight binding model of Bogolyubov-de Gennes (BdG) Hamiltonian is applied to study the phase diagram of bulks, and the chiral Majorana edge states in nanoribbons. Numerical results show that difference between the superconducting pairing parameters at two sublattices is necessary to induce topological superconductor phase. The additional proximity to ferromagnetic substrate modifies the phase diagram, in which uniform superconducting pairing parameters could induce topological superconductor phase. The BdG Chern number of certain topological superconductor phases is ±1, so that the corresponding nanoribbons have only one pair of chiral Majorana edge states.

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Effective model for Majorana modes in graphene

Cited by 11 publications

References 37 publications

Mechanisms of Andreev reflection in quantum Hall graphene

Mechanisms of Andreev reflection in quantum Hall graphene

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

Chiral Majorana Fermions in two dimensional square lattice antiferromagnet with proximity-induced superconductivity

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