Topological phase transition driven by magnetic field and topological Hall effect in an antiferromagnetic skyrmion lattice

Tome, María C. Fernández; Rosales, H. D.

doi:10.1103/physrevb.103.l020403

Cited by 25 publications

(17 citation statements)

References 50 publications

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“…Another example is a bilayer structure system where the sign of the DM interaction is opposite for the different two layers [103][104][105][106]. Although the above lattice structures with the sublattice degree of freedom have attracted great interest owing to the findings of an antiferromagnetic (AFM) SkX [107][108][109][110][111][112] and intriguing dynamics [113][114][115][116][117][118][119], the effect of the sublattice-dependent DM interaction on the stabilization of the SkX has not been fully clarified yet [120,121].…”

Section: Introductionmentioning

confidence: 99%

Skyrmion crystal and spiral phases in centrosymmetric bilayer magnets with staggered Dzyaloshinskii-Moriya interaction

Hayami

2021

Preprint

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We theoretically study a stabilization mechanism of the skyrmion crystal in centrosymmetric magnets with a bilayer structure. We show that the interplay between a layer-dependent staggered Dzyaloshinskii-Moriya interaction that arises from the absence of local inversion symmetry and the interlayer exchange interaction gives rise to a plethora of multiple-Q states including the skyrmion crystal with a quantized topological number. By performing the simulated annealing for the bilayer triangular-lattice model under an external magnetic field, we demonstrate that the skyrmion forms the triangular-shaped crystals with different helicities in each layer owing to the staggered Dzyaloshinskii-Moriya interaction. Although the relative positions of the skyrmion core in each layer are different depending on the sign of the interlayer exchange interactions, the skyrmion crystal phases robustly appear under both ferromagnetic and antiferromagnetic interlayer interactions. We also find another two triple-Q states with a uniform scalar chirality but without a quantized topological number in the low-and high-field regions. Especially, the low-field triple-Q state exhibits the opposite sign of the scalar chirality to the skyrmion crystal, which are not found in the single-layer system. Our results indicate that the lack of local inversion symmetry in the lattice structure is another key ingredient to induce topological spin textures in centrosymmetric magnets.

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Section: Introductionmentioning

confidence: 99%

Skyrmion crystal and spiral phases in centrosymmetric bilayer magnets with staggered Dzyaloshinskii-Moriya interaction

Hayami

2021

Preprint

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“…This indicates that the Hall conductivity is not quantized and vanishes in the case of the insulators. In this context, this state is regarded as an antiferromagnetic SkX, which has been investigated in the square, triangular, and honeycomb magnets [156][157][158][159][160][161][162]. However, the present antiferromagnetic SkX (Phase VI) consists of different skyrmion numbers −1 and 2, which is different from the previous findings.…”

Section: Resultsmentioning

confidence: 67%

Multifarious skyrmion phases on a trilayer triangular lattice

Hayami

2022

Preprint

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The instability toward a magnetic skyrmion crystal in centrosymmetric trilayer magnets is investigated based on a spin model with layer-dependent Dzayloshinskii-Moriya interaction. We find various types of skyrmion crystal phases with different skyrmion numbers in a low-temperature phase diagram by performing the simulated annealing. In addition to the Néel skyrmion crystal phase that is expected to emerge in the presence of the polar-type Dzayloshinskii-Moriya interaction, we obtain the skyrmion crystal phases characteristics of the layered system: the twisted surface skyrmion crystal, anti-skyrmion crystal, and high-topological-number skyrmion crystal phases. The rich magnetic phases are brought about by the synergy among the layer-dependent Dzayloshinskii-Moriya interaction, interlayer exchange interaction, and an external magnetic field. Our results indicate that the layer degree of freedom at the surface and heterostructures provides a good platform to engineer and design the topological spin textures.

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“…In the strong Hund coupling limit J H t, the spin of the itinerant electron is fully aligned with magnetic moment S r . Therefore, it is trivial to observe that the electronic spectrum splits into a low-and high-energy band set 34,43 .…”

Section: Appendix: Effective Hamiltonian Derivationmentioning

confidence: 99%

“…In particular, AFM skyrmions have become the subject of intense focus in the context of antiferromagnetic spintronics 32 . The interest in AFM skyrmions arises from the effect of coupling conduction electrons to the local magnetic background: the electrons accumulate a Berry phase as they travel through skyrmions spin configuration, which acts as a local effective magnetic field leading to topological Hall effect (THE) 33,34 and the skyrmion Hall effect 14,[35][36][37] . Compared with FM skyrmions, AFM ones can move along the direction of the driving force without showing the skyrmion Hall effect.…”

Section: Introductionmentioning

confidence: 99%

Skyrmion-skyrmion interaction induced by itinerant electrons in a ferromagnetic strip

Iroulart¹,

Rosales²

2021

Preprint

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Magnetic skyrmions are promising spin textures for building next-generation magnetic memories and spintronic devices. Nevertheless, one of the major challenges in realizing skyrmion-based devices is the stabilization of ordered arrays of these spin textures in different geometries. Here we numerically study the skyrmion-skyrmion interaction potential that arises due to the dynamics of itinerant electrons coupled to the magnetic texture in a ferromagnetic background with racetrack geometry. We consider different topological textures (ferromagnetic (FM) and antiferromagnetic (AFM)), namely: skyrmions, antiskyrmions and biskyrmions. We show that at low electron filling, for sufficiently short separation, the skyrmions strongly couple each other yielding a bound-state bound by electronic dynamics. However, when the filling is increased, the interaction potential energy presents local minima at specific values of the skyrmion-skyrmion distance. Each of these local minima correspond to energetically stable positions of skyrmions which are "protected" by well defined energy barriers. By inspecting the local charge density, we find that in the case of AFM skyrmions, the local antiferromagnetic nature prevents electronic penetration into the core, allowing the AFM skyrmions to be seen as infinite potential barriers for electrons.

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Topological phase transition driven by magnetic field and topological Hall effect in an antiferromagnetic skyrmion lattice

Cited by 25 publications

References 50 publications

Skyrmion crystal and spiral phases in centrosymmetric bilayer magnets with staggered Dzyaloshinskii-Moriya interaction

Skyrmion crystal and spiral phases in centrosymmetric bilayer magnets with staggered Dzyaloshinskii-Moriya interaction

Multifarious skyrmion phases on a trilayer triangular lattice

Skyrmion-skyrmion interaction induced by itinerant electrons in a ferromagnetic strip

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