General method for atomistic spin-lattice dynamics with first-principles accuracy

Hellsvik, Johan; Thonig, Danny; Modin, Klas; Iuşan, Diana; Bergman, Anders; Eriksson, Olle; Bergqvist, Lars; Delin, Anna

doi:10.1103/physrevb.99.104302

Cited by 61 publications

(71 citation statements)

References 132 publications

(141 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The coupled dynamics of phonons and magnons can currently be parametrized from first-principles calculations and then solved exactly in the limit of classical spins [91,92] or approximately in quantum flavor [93]. We foresee that such investigation for CrX 3 systems will be done in the near future.…”

Section: Discussionmentioning

confidence: 99%

Relativistic exchange interactions in CrX3 ( X=Cl , Br, I) monolayers

et al. 2020

View full text Add to dashboard Cite

It has been predicted theoretically and indirectly confirmed experimentally that single-layer CrX 3 (X = Cl, Br, I) might be the prototypes of topological magnetic insulators (TMI). In this work, by using first-principles calculations combined with atomistic spin dynamics, we provide a complete picture of the magnetic interactions and magnetic excitations in CrX 3. The focus is here on the two most important aspects for the actual realization of TMI, namely the relativistic magnetic interactions and the finite-size (edge) effects. We compute the full interaction tensor, which includes both Kitaev and Dzyaloshinskii-Moriya (DM) terms, which are considered as the most likely mechanisms for stabilizing topological magnons. First, we instigate the properties of bulk CrI 3 and compare the simulated magnon spectrum with the experimental data [Phys. Rev. X 8, 041028 (2018)]. Our results suggest that a large size of topological gap, seen in experiment (≈4 meV), cannot be explained by considering pair-wise spin interactions only. We identify several possible reasons for this disagreement. The magnetic interactions in the monolayers of CrX 3 are also investigated. The strength of the anisotropic interactions is shown to scale with the position of halide atom in the periodic table, the heavier the element the larger is the anisotropy, in agreement with prior studies. Comparing the magnons for the bulk and single-layer CrI 3 , we find that the size of the topological gap becomes smaller in the latter case. The obtained next nearest-neighbor DM vector is oriented primarily in-plane of the monolayer and has relatively small z component, which results in a small value of the topological gap. Finally, we investigate finite-size effects in monolayers and demonstrate that the anisotropic couplings between Cr atoms close to the edges are much stronger than those in ideal periodic structure. This should have impact on the dynamics of the magnon edge modes in Cr halides.

show abstract

Section: Discussionmentioning

confidence: 99%

Relativistic exchange interactions in CrX3 ( X=Cl , Br, I) monolayers

et al. 2020

View full text Add to dashboard Cite

show abstract

“…where r c is the cutoff and Θ(r c − r i j ) is the Heaviside step function, which implies no exchange coupling between spins situated at larger distance than r c . Several previous SLD models suffered from the fact that they did not allow angular momentum transfer between lattice and spin systems 28 . This happened for magnetisation dynamics in the absence of spin thermostat, governed by symmetric exchange only, due to total angular momentum conservation.…”

Section: Computational Modelmentioning

confidence: 99%

“…A complete description of magnetic systems includes the interaction between several degrees of freedom, such as lattice, spins and electrons, modeled in a self-consistent simulation framework. The characteristic relaxation timescales of electrons are much smaller (≈ fs) in comparison to spin and lattice (100 fs − ps), hence magnetisation relaxation processes can be described via coupled spin and lattice dynamics, termed Spin-Lattice Dynamics (SLD) [22][23][24][25][26][27][28][29] . SLD models can be crucial in disentangling the interplay between these sub-systems.…”

Section: Introductionmentioning

confidence: 99%

“…SLD models have so far considered either microcanonical (NVE -constant particle number, volume and energy) 27,28 or canonical (NVT -constant particle number, volume and temperature) ensembles with two Langevin thermostats connected to both lattice and spin subsystems 23,32 . Damping due to spinlattice interactions only within the canonical ensemble (NVT)…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spin-lattice dynamics model with angular momentum transfer for canonical and microcanonical ensembles

et al. 2021

View full text Add to dashboard Cite

A unified model of molecular and atomistic spin dynamics is presented enabling simulations both in microcanonical and canonical ensembles without the necessity of additional phenomenological spin damping. Transfer of energy and angular momentum between the lattice and the spin systems is achieved by a phenomenological coupling term representing the spin-orbit interaction. The characteristic spectra of the spin and phonon systems are analyzed for different coupling strength and temperatures. The spin spectral density shows magnon modes together with the uncorrelated noise induced by the coupling to the lattice. The effective damping parameter is investigated showing an increase with both coupling strength and temperature. The model paves the way to understanding magnetic relaxation processes beyond the phenomenological approach of the Gilbert damping and the dynamics of the energy transfer between lattice and spins.

show abstract

“…Ionic Raman scattering was predicted half a century ago [39][40][41] and has been demonstrated recently for nonlinear phonon interactions [42][43][44]. The approach presented here can be straightforwardly extended for non-Raman mechanisms, such as one-photon and one-phonon [34,[45][46][47][48][49][50][51][52][53][54] as well as twomagnon processes [55,56], which will be the matter of future work. Our results pave the way for future experiments utilizing phono-magnetic effects in the ultrafast control of magnetic order.…”

mentioning

confidence: 83%

Phono-magnetic analogs to opto-magnetic effects

Juraschek

Narang

Spaldin

2020

Phys. Rev. Research

View full text Add to dashboard Cite

The magneto-optical and opto-magnetic effects describe the interaction of light with a magnetic medium. The most prominent examples are the Faraday and Cotton-Mouton effects that modify the transmission of light through a medium, and the inverse Faraday and inverse Cotton-Mouton effects that produce effective magnetic fields for the spin in the material. Here, we introduce the phenomenology of the analogous magneto-phononic and phono-magnetic effects, in which vibrational quanta take the place of the light quanta. We show, using a combination of first-principles calculations and phenomenological modeling, that the effective magnetic fields exerted by the phonon analogs of the inverse Faraday and inverse Cotton-Mouton effects on the spins of antiferromagnetic nickel oxide yield magnitudes comparable to and potentially larger than those of the opto-magnetic originals.

show abstract

General method for atomistic spin-lattice dynamics with first-principles accuracy

Cited by 61 publications

References 132 publications

Relativistic exchange interactions in CrX3 ( X=Cl , Br, I) monolayers

Relativistic exchange interactions in CrX3 ( X=Cl , Br, I) monolayers

Spin-lattice dynamics model with angular momentum transfer for canonical and microcanonical ensembles

Phono-magnetic analogs to opto-magnetic effects

Contact Info

Product

Resources

About