Different dimensionality trends in the Landau damping of magnons in iron, cobalt, and nickel: Time-dependent density functional study

Buczek, Paweł; Ernst, A.; Sandratskii, L. M.

doi:10.1103/physrevb.84.174418

Cited by 87 publications

(119 citation statements)

References 131 publications

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“…Another way of understanding the wave vector-dependent lifetime is to calculate the so-called Landau map and look for the Landau hot spots (the more the Landau hot spots, the larger the damping.) 11,12 . Two Landau maps are provided in Supplementary Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Discussion Our next step is to understand the physics of the long magnons' lifetime in this system with the aid of first-principles calculations within the framework of linear-response time-dependent density functional theory 12 . These calculations account properly for the magnons' lifetime as they consider, on an equal footing, the collective magnetic excitations and single-particle Stoner excitations.…”

Section: Resultsmentioning

confidence: 99%

“…These calculations are performed for the case of Fe 50 Pd 50 alloy films. A third set of calculations was performed on the basis of linear-response timedependent density functional theory 12 . This type of calculations provide information on the magnon lifetime in addition to the dispersion relation.…”

Section: Methodsmentioning

confidence: 99%

“…As a result, the terahertz magnons in metallic ferromagnets feature a very short lifetime, only up to a few tens of femtoseconds 5,[11][12][13][14]17 . The decay of magnons into Stoner excitations is usually referred to as Landau damping.…”

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confidence: 99%

“…This means that the use of high-frequency (terahertz) magnons would provide a great opportunity for the design of ultrafast devices. However, one of the main challenges for using terahertz magnons is their short lifetime in metallic ferromagnets [5][6][7][8][9][10][11][12][13][14][15][16] . Hence, the discovery of a low-damping material would push the progress in the field of terahertz magnonics one big step further.…”

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confidence: 99%

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Long-living terahertz magnons in ultrathin metallic ferromagnets

et al. 2015

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The main idea behind magnonics is to use the elementary magnetic excitations (magnons) for information transfer and processing. One of the main challenges, hindering the application of ultrafast terahertz magnons in magnonics, has been the short lifetime of these excitations in metallic ferromagnets. Here, we demonstrate that the engineering of the electronic structure of a ferromagnetic metal, by reducing its dimensionality and changing its chemical composition, opens a possibility to strongly suppress the relaxation channels of terahertz magnons and thereby enhance the magnons' lifetime. For the first time, we report on the long-lived terahertz magnons excited in ultrathin metallic alloy films. On the basis of the first-principles calculations, we explain the microscopic nature of the long lifetime being a consequence of the peculiar electronic hybridizations of the species. We further demonstrate a way of tailoring magnon energies (frequencies) by varying the chemical composition of the film.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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confidence: 99%

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Long-living terahertz magnons in ultrathin metallic ferromagnets

et al. 2015

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Ab‐Initio Real‐Time Magnon Dynamics in Ferromagnetic and Ferrimagnetic Systems

Singh

Elliott

Dewhurst

et al. 2020

Physica Status Solidi (b)

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Magnonics—an emerging field of physics—is based on the collective excitations of ordered spins called spin waves. These low‐energy excitations carry pure spin currents, paving the way for future technological devices working at low energies and on ultrafast timescales. The traditional ab‐initio approach to predict these spin‐wave energies is based on linear‐response time‐dependent density functional theory (LR‐TDDFT) in the momentum and frequency regime. Herein, the simulation of magnon dynamics using real‐time time‐dependent density functional theory is demonstrated, thus extending the domain of ab‐initio magnonic studies. Unlike LR‐TDDFT, this enables us to observe atom‐resolved dynamics of individual magnon modes and, using a supercell approach, the dynamics of several magnon modes can be observed simultaneously. The energies of these magnon modes are concurrent with those found using LR‐TDDFT. Next, the complex dynamics of the superposition of magnon modes is studied, before finally studying the element‐resolved modes in multisublattice magnetic systems.

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Spin Excitations in Solids from Many-Body Perturbation Theory

Friedrich

Şaşıoğlu

Müller

et al. 2014

Topics in Current Chemistry

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Collective spin excitations form a fundamental class of excitations in magnetic materials. As their energy reaches down to only a few meV, they are present at all temperatures and substantially influence the properties of magnetic systems. To study the spin excitations in solids from first principles, we have developed a computational scheme based on many-body perturbation theory within the full-potential linearized augmented plane-wave (FLAPW) method. The main quantity of interest is the dynamical transverse spin susceptibility or magnetic response function, from which magnetic excitations, including single-particle spin-flip Stoner excitations and collective spin-wave modes as well as their lifetimes, can be obtained. In order to describe spin waves we include appropriate vertex corrections in the form of a multiple-scattering T matrix, which describes the coupling of electrons and holes with different spins. The electron-hole interaction incorporates the screening of the many-body system within the random-phase approximation. To reduce the numerical cost in evaluating the four-point T matrix, we exploit a transformation to maximally localized Wannier functions that takes advantage of the short spatial range of electronic correlation in the partially filled d or f orbitals of magnetic materials. The theory and the implementation are discussed in detail. In particular, we show how the magnetic response function can be evaluated for arbitrary k points. This enables the calculation of smooth dispersion curves, allowing one to study fine details in the k dependence of the spin-wave spectra. We also demonstrate how spatial and time-reversal symmetry can be exploited to accelerate substantially the computation of the four-point quantities. As an illustration, we present spin-wave spectra and dispersions for the elementary ferromagnet bcc Fe, B2-type tetragonal FeCo, and CrO₂ calculated with our scheme. The results are in good agreement with available experimental data.

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Different dimensionality trends in the Landau damping of magnons in iron, cobalt, and nickel: Time-dependent density functional study

Cited by 87 publications

References 131 publications

Long-living terahertz magnons in ultrathin metallic ferromagnets

Long-living terahertz magnons in ultrathin metallic ferromagnets

Ab‐Initio Real‐Time Magnon Dynamics in Ferromagnetic and Ferrimagnetic Systems

Spin Excitations in Solids from Many-Body Perturbation Theory

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