Selective flattening of magnon bands in kagome-lattice ferromagnets with Dzyaloshinskii-Moriya interaction

Xing, Yufeng; Ma, Fusheng; Zhang, LiFa; Zhang, Zhenyu

doi:10.1007/s11433-019-1532-1

Cited by 4 publications

(6 citation statements)

References 54 publications

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“…Since each unit cell contains three Fe atoms (Fig. 1e), we expect one acoustic and two optical spin-wave branches in a local moment Heisenberg Hamiltonian 34,38,39 . Figure 1f, g show the reciprocal spaces corresponding to the crystal structures of FeSn depicted in Fig.…”

Section: Resultsmentioning

confidence: 99%

Spin excitations in metallic kagome lattice FeSn and CoSn

Xie

Chen

et al. 2021

Commun Phys

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In two-dimensional (2D) metallic kagome lattice materials, destructive interference of electronic hopping pathways around the kagome bracket can produce nearly localized electrons, and thus electronic bands that are flat in momentum space. When ferromagnetic order breaks the degeneracy of the electronic bands and splits them into the spin-up majority and spin-down minority electronic bands, quasiparticle excitations between the spin-up and spin-down flat bands should form a narrow localized spin-excitation Stoner continuum coexisting with well-defined spin waves in the long wavelengths. Here we report inelastic neutron scattering studies of spin excitations in 2D metallic kagome lattice antiferromagnetic FeSn and paramagnetic CoSn, where angle resolved photoemission spectroscopy experiments found spin-polarized and nonpolarized flat bands, respectively, below the Fermi level. Our measurements on FeSn and CoSn reveal well-defined spin waves extending above 140 meV and correlated paramagnetic scattering around Γ point below 90 meV, respectively. In addition, we observed non-dispersive excitations at ~170 meV and ~360 meV arising mostly from hydrocarbon scattering of the CYTOP-M used to glue the samples to aluminum holder. Therefore, our results established the evolution of spin excitations in FeSn and CoSn, and identified anomalous flat modes overlooked by the neutron scattering community for many years.

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Section: Resultsmentioning

confidence: 99%

Spin excitations in metallic kagome lattice FeSn and CoSn

Xie

Chen

et al. 2021

Commun Phys

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“…Because FeSn is ordered antiferromagnetically along the c axis with Neel temperature determined by the c-axis magnetic exchange coupling [32] , we expect that the in-plane spin excitations and magnetic flat band with much large magnetic exchange couplings to persist in the paramagnetic state at temperature just above T N , analogous to strong correlated in-plane spin fluctuations seen in iron pnictides above the AF ordering temperature [38] . We remark that flat spin wave flat bands can occur in insulating kagome lattice ferromagnets with Dzyaloshinskii-Moriya (DM) interactions [33] , but these have an entirely different origin [34] .…”

mentioning

confidence: 90%

“…Since each unit cell contains three Fe atoms [Fig. 1(e)], we expect one acoustic and two optical spin-wave branches in a local moment Heisenberg Hamiltonian [32][33][34] . Figures 1(f, ferromagnetic kagome planes.…”

mentioning

confidence: 99%

Spin excitations in metallic kagome lattice FeSn and CoSn

Xie,

Chen,

Chen

et al. 2021

Preprint

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“…These unusual fluctuation properties suggest that electronic itineracy contributes plays a role in both the observed static ordered moment of FeSn 34 . We remark that flat spin wave flat bands can occur in kagome lattice ferromagnets with Dzyaloshinskii-Moriya (DM) interactions 37 , but these have an entirely different origin 38 .…”

Section: Resultsmentioning

confidence: 90%

“…Since each unit cell contains three Fe atoms [Fig. 1(e)], we expect one acoustic and two optical spin-wave branches in a local moment Heisenberg Hamiltonian 34,37,38 . Figures 1(f,g)…”

Section: Resultsmentioning

confidence: 99%

Spin excitations in metallic kagome lattice FeSn and CoSn

Xie

Chen

et al. 2021

Preprint

View full text Add to dashboard Cite

In two-dimensional (2D) metallic kagome lattice materials, destructive interference of electronic hopping pathways around the kagome bracket can produce nearly localized electrons, and thus electronic bands that are flat in momentum space. When ferromagnetic order breaks the degeneracy of the electronic bands and splits them into the spin-up majority and spin-down minority electronic bands, quasiparticle excitations between the spin-up and spin-down flat bands should form a narrow localized spin-excitation Stoner continuum coexisting with well-defined spin waves in the long wavelengths. Here we report inelastic neutron scattering studies of spin excitations in 2D metallic Kagome lattice antiferromagnetic FeSn and paramagnetic CoSn, where angle resolved photoemission spectroscopy experiments found spin-polarized and nonpolarized flat bands, respectively, below the Fermi level. Although our initial measurements on FeSn indeed reveal well-defined spin waves extending well above 140 meV coexisting with a flat excitation at 170 meV, subsequent experiments on CoSn indicate that the flat mode actually arises mostly from hydrocarbon scattering of the CYTOP-M commonly used to glue the samples to aluminum holder. Therefore, our results established the evolution of spin excitations in FeSn and CoSn, and identified an anomalous flat mode that has been overlooked by the neutron scattering community for the past 20 years.

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Selective flattening of magnon bands in kagome-lattice ferromagnets with Dzyaloshinskii-Moriya interaction

Cited by 4 publications

References 54 publications

Spin excitations in metallic kagome lattice FeSn and CoSn

Spin excitations in metallic kagome lattice FeSn and CoSn

Spin excitations in metallic kagome lattice FeSn and CoSn

Spin excitations in metallic kagome lattice FeSn and CoSn

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