Topological magnon bands in a room-temperature kagome magnet

Zhang, Heda; Feng, Xiaozhou; Heitmann, Thomas; Kolesnikov, A. I.; Stone, M. B.; Lü, Yuan; Ke, Xianglin

doi:10.1103/physrevb.101.100405

Cited by 51 publications

(55 citation statements)

References 40 publications

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“…The former temperature corresponds to the paramagnetism-antiferromagnetism phase transition. The latter corresponds to a transition from an AFM order along the c-axis above T hel to a c-axis helical order with in-plane FM order at low temperature, consistent with the previous results [33][34][35][36]. Moreover, the temperature dependence of longitudinal resistivity ρ xx and ρ zz with zero-field shows a metallic behavior with weak anisotropy, similar to GdMn 6 Sn 6 [37].…”

Section: Resultssupporting

confidence: 89%

“…When the Mn 3d local moments are partially frozen and form long-range static FM order in the hexagonal ab plane, the mass enhancements of the Mn 3d electrons near the E F are substantially reduced to about 2-3. The fluctuating local moment of Mn 3d electrons remains the same value as in the PM state whereas the statically ordered moment is 2.1 µ B , which is in excellent agreement with experimental measurement [33,38].…”

Section: Resultssupporting

confidence: 89%

“…The Sn2 atoms form the honeycomb lattice located at the center of Mn-Sn1-Sn2-Sn1-Mn slab. As for the Mn kagome layers, neutron diffraction experiments reported FM coupling in each kagome bilayer, along with c-axis AFM coupling between the bilayer to the next bilayer below room temperature [33,34]. Figure 1d shows the 3D BZ with high-symmetry points and projected BZ along c-axis.…”

Section: Resultsmentioning

confidence: 96%

See 2 more Smart Citations

Spin-polarized Dirac cone, flat band and saddle point in kagome magnet YMn6Sn6

Li¹,

Wang²,

Wang³

et al. 2020

Preprint

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Kagome-lattice of 3d-transition metals hosting Weyl/Dirac fermions and topological flat bands exhibit non-trivial topological characters and novel quantum phases, such as anomalous Hall eﬀect and fractional quantum Hall eﬀect. With consideration of spin-orbit coupling and electron correlation, several instabilities could be induced. The complete characters of the electronic structure of kagome lattice, i.e. the saddle point, Dirac-cone, and flat band, around the Fermi energy (EF) remain elusive in magnetic kagome materials. We present the first experimental observation of the complete features in ferromagnetic kagome layers of YMn6Sn6 helically coupled along the c-axis, by using angle-resolved photoemission spectroscopy and band structure calculations. We demonstrate a Dirac dispersion near EF arising from a spin-polarized orbital, which carries an intrinsic Berry curvature and contributes to the anomalous Hall eﬀect in transport measurements. In addition, a flat band and a saddle point with a high density of states and with orbital-selective characters near EF are observed. These multi-orbital kagome features could cause multi-orbital magnetism. The Dirac fermion, flat band and saddle point in the vicinity of EF open an opportunity in manipulating the topological properties in magnetic materials.

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Section: Resultssupporting

confidence: 89%

Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 96%

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Spin-polarized Dirac cone, flat band and saddle point in kagome magnet YMn6Sn6

Li¹,

Wang²,

Wang³

et al. 2020

Preprint

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“…Even for small skyrmions (D/J = 1), quantum damping of the A and B modes is negligible. Hence, SkXs are an excellent platform for low-energy topological magnonics, which is at variance with other topological magnets [125][126][127] whose chiral edge magnons appear at high energies of the order of the exchange energy.…”

Section: Discussionmentioning

confidence: 98%

Quantum damping of skyrmion crystal eigenmodes due to spontaneous quasiparticle decay

Mook

Klinovaja

Loss

2020

Phys. Rev. Research

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Skyrmion crystals support chiral magnonic edge states akin to electronic quantum Hall edge states. However, magnonic topology relies on the harmonic approximation, neglecting ubiquitous magnon-magnon interactions that yield a finite zero-temperature quantum damping. We demonstrate that spontaneous quasiparticle decay in two-dimensional ferromagnetic skyrmion crystals is a delicate issue, with the quantum damping ranging over several orders of magnitude. Flat magnon bands cause exceptionally strong spontaneous decay at twice their energy. The resulting externally controllable energy-selective magnon breakdown is measurable not only by scattering but also by magnetic resonance experiments, probing the magnetically active anticlockwise, breathing, and clockwise modes. They exhibit distinct decay behavior, with the clockwise (anticlockwise) mode being the least (most) stable mode out of the three. The quantum damping of the topologically nontrivial anticlockwise mode is negligible, establishing the harmonic theory as a trustworthy approximation at low energies, implying excellent prospects of topological magnonics in skyrmion crystals.

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“…Generally the Curie-temperatures of most of the magnetic materials are lower than room-temperature and even at higher temperature (less than Curie-temperature) the width of the magnon bands broden and possibly a topological phase transition can occur due to band-gap closing. So, it was thought previously that topological magnon Hall effect is only possible at low temperatures, until recently the discovery of topological magnon Hall-effect in Kagome ferromagnet YMn 6 Sn 6 at room temperature [46]. Kagome lattice with antiferromagnetic nearest neighbour Heisenberg interaction is a frustrated magnetic system and frustration of magnetic lattices is a key ingredient to generate non-coplanar magnetic ground states (e.g.…”

Section: Background and Motivationsmentioning

confidence: 99%

Topological excitations in quasi two-dimensional quantum magnets with weak interlayer interactions

Bhowmick¹

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Topological magnon bands in a room-temperature kagome magnet

Cited by 51 publications

References 40 publications

Spin-polarized Dirac cone, flat band and saddle point in kagome magnet YMn6Sn6

Spin-polarized Dirac cone, flat band and saddle point in kagome magnet YMn6Sn6

Quantum damping of skyrmion crystal eigenmodes due to spontaneous quasiparticle decay

Topological excitations in quasi two-dimensional quantum magnets with weak interlayer interactions

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