Quantum anomalous Hall effect in graphene coupled to skyrmions

Lado, José L.; Fernández-Rossier, J.

doi:10.1103/physrevb.92.115433

Cited by 34 publications

(35 citation statements)

References 35 publications

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“…We have also found that the sign of the Chern number is controlled by the sign of the applied magnetic field. Changing the sign of D results in a change of the skyrmion winding numbers, but it does not change the sign of the spin-wave Chern numbers, in contrast with the case of the electronic Chern number in a skyrmion lattice [47].…”

Section: Topological Magnonic Bandsmentioning

confidence: 92%

Topological spin waves in the atomic-scale magnetic skyrmion crystal

2016

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We study the spin waves of the triangular skyrmion crystal that emerges in a two-dimensional spin lattice model as a result of the competition between Heisenberg exchange, Dzyalonshinkii-Moriya interactions, Zeeman coupling and uniaxial anisotropy. The calculated spin wave bands have a finite Berry curvature that, in some cases, leads to non-zero Chern numbers, making this system topologically distinct from conventional magnonic systems. We compute the edge spin-waves, expected from the bulk-boundary correspondence principle, and show that they are chiral, which makes them immune to elastic backscattering. Our results illustrate how topological phases can occur in self-generated emergent superlattices at the mesoscale.

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Section: Topological Magnonic Bandsmentioning

confidence: 92%

Topological spin waves in the atomic-scale magnetic skyrmion crystal

2016

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“…In the following and especially in the last 20 years it has been found that the external magnetic field is not mandatory to produce a Hall effect and can be exchanged for example by spin-orbit coupling [2] or a chiral magnetic texture [3] that produces an effective magnetic field, that is a "Berry curvature" [4]. The family of Hall effects for electrons in solids was extended by the quantum Hall effect [5][6][7], anomalous Hall effect [2], quantum anomalous Hall effect [8,9], spin Hall effect [10,11], quantum spin Hall effect [12,13], and topological Hall effect [3,[14][15][16][17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

The family of topological Hall effects for electrons in skyrmion crystals

et al. 2018

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Abstract. Hall effects of electrons can be produced by an external magnetic field, spin-orbit coupling or a topologically non-trivial spin texture. The topological Hall effect (THE) -caused by the latter -is commonly observed in magnetic skyrmion crystals. Here, we show analogies of the THE to the conventional Hall effect (HE), the anomalous Hall effect (AHE), and the spin Hall effect (SHE). In the limit of strong coupling between conduction electron spins and the local magnetic texture the THE can be described by means of a fictitious, "emergent" magnetic field. In this sense the THE can be mapped onto the HE caused by an external magnetic field. Due to complete alignment of electron spin and magnetic texture, the transverse charge conductivity is linked to a transverse spin conductivity. They are disconnected for weak coupling of electron spin and magnetic texture; the THE is then related to the AHE. The topological equivalent to the SHE can be found in antiferromagnetic skyrmion crystals. We substantiate our claims by calculations of the edge states for a finite sample. These states reveal in which situation the topological analogue to a quantized HE, quantized AHE, and quantized SHE can be found.

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“…The < i, j > symbol implies summation over all nearest neighboring pairs of atoms, and we are assuming that the magnitude of the magnetization is uniform over the whole graphene lattice. This Hamiltonian has been considered before 23 for the case of 2D graphene interacting with a skyrmion crystal. In contrast, here we consider a graphene device that hosts an individual skyrmion.…”

Section: Tight-binding Quantum Transport Approachmentioning

confidence: 99%

Electrical detection of individual skyrmions in graphene devices

2017

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We study a graphene Hall probe located on top of a magnetic surface as a detector of skyrmions, using as working principle the anomalous Hall effect produced by the exchange interaction of the graphene electrons with the non-coplanar magnetization of the skyrmion. We study the magnitude of the effect as a function of the exchange interaction, skyrmion size and device dimensions. Our calculations for multiterminal graphene nanodevices, working in the ballistic regime, indicate that for realistic exchange interactions a single skyrmion would give Hall voltages well within reach of the experimental state of the art. The proposed device could act as an electrical transducer that marks the presence of a single skyrmion in a nanoscale region, paving the way towards the integration of skyrmion-based spintronics and graphene electronics.

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Quantum anomalous Hall effect in graphene coupled to skyrmions

Cited by 34 publications

References 35 publications

Topological spin waves in the atomic-scale magnetic skyrmion crystal

Topological spin waves in the atomic-scale magnetic skyrmion crystal

The family of topological Hall effects for electrons in skyrmion crystals

Electrical detection of individual skyrmions in graphene devices

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