Theory of noncollinear interactions beyond Heisenberg exchange: Applications to bcc Fe

Szilva, Attila; Thonig, Danny; Bessarab, Pavel F.; Kvashnin, Yaroslav; Rodrigues, Diego de Macedo; Cardias, Ramon; Pereiro, Manuel; Nordström, Lars; Bergman, Anders; Klautau, A. B.; Eriksson, Olle

doi:10.1103/physrevb.96.144413

Cited by 33 publications

(25 citation statements)

References 31 publications

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“…The Heisenberg bi-linear exchange interactions J ij and the DM vectors D ij were calculated with the use of the Liechtenstein-Katsnelson-Antropov-Gubanov (LKAG) formula [22,23], as implemented in the RS-LMTO-ASA method [13,35,[42][43][44]. Both J ij and D ij have been obtained from the ferromagnetic configuration of the nanoclusters.…”

Section: Computational Detailsmentioning

confidence: 99%

Incommensurate spin and orbital magnetism of Mn atomic chains on W(110) surface

Bezerra-Neto,

Kvashnin,

Bergman

et al. 2021

Preprint

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Stabilization of unusual spin-orbit driven magnetic orderings are achieved for chains of Mn atoms deposited on a W(110) substrate. First-principles electronic structure calculations show that the ground state spin configuration is non-collinear, forming spirals as a result of a competition between nearest and next-nearest neighbour exchange interactions. The orbital magnetic moments are also found to exhibit non-collinear ordering, that interestingly for some systems is incommensurate with the spin arrangement. We attribute such an exotic behaviour to the competition between the and spin-orbital interaction and crystal-field splitting effects. Model calculations based on this assumption reproduce the main findings observed in the first-principles calculations.

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Section: Computational Detailsmentioning

confidence: 99%

Incommensurate spin and orbital magnetism of Mn atomic chains on W(110) surface

Bezerra-Neto,

Kvashnin,

Bergman

et al. 2021

Preprint

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“…While the original work by Liechtenstein et al considered ferromagnetic ground states, extensions of the LKAG formalism to non-equilibrium [13,14] and non-collinear [15][16][17][18][19][20][21] states have been considered. However, it was realized that a mapping of non-collinear spin configurations to a Heisenberg model [19] or to a generalized Heisenberg model with a bilinear exchange tensor [17] is in general not possible for non-collinear states, apparently requiring the inclusion of higher order (beyond Heisenberg) exchange contributions [3,9,22]. We propose an alternative solution by including a linear term in a generalized spin model.…”

Section: Introductionmentioning

confidence: 99%

Exchange constants for local spin Hamiltonians from tight-binding models

Streib,

Szilva,

Borisov

et al. 2021

Preprint

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We consider the mapping of tight-binding electronic structure theory to a local spin Hamiltonian, based on the adiabatic approximation for spin degrees of freedom in itinerant-electron systems. Local spin Hamiltonians are introduced in order to describe the energy landscape of small magnetic fluctuations, locally around a given spin configuration. They are designed for linear response near a given magnetic state and in general insufficient to capture arbitrarily strong deviations of spin configurations from the equilibrium. In order to achieve this mapping, we include a linear term in the local spin Hamiltonian that, together with the usual bilinear exchange tensor, produces an improved accuracy of effective magnetic Weiss fields for non-collinear states. We also provide examples from tight-binding electronic structure theory, where our implementation of the calculation of exchange constants is based on constraining fields that stabilize an out-of-equilibrium spin configuration. We check our formalism by means of numerical calculations for iron dimers and chains.

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“…magnon excitations 16 , which are important for fields such as spintronics and its technological applications. However, it was shown that these parameters are strongly affected by non-collinearity in case of non-Heisenberg systems 25 and, therefore, the properties need to be calculated under a non-collinear formalism. In fact, it has been shown that the calculation of magnon excitations in bcc Fe are closer to the experimental results if one takes into account the calculation of J ij in the non-collinear (NC) framework 26 .…”

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confidence: 99%

First-principles Dzyaloshinskii–Moriya interaction in a non-collinear framework

Cardias

Szilva

Bezerra-Neto

et al. 2020

Sci Rep

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We have derived an expression of the Dzyaloshinskii–Moriya interaction (DMI), where all the three components of the DMI vector can be calculated independently, for a general, non-collinear magnetic configuration. The formalism is implemented in a real space—linear muffin-tin orbital—atomic sphere approximation (RS-LMTO-ASA) method. We have chosen the Cr triangular trimer on Au(111) and Mn triangular trimers on Ag(111) and Au(111) surfaces as numerical examples. The results show that the DMI (module and direction) is drastically different between collinear and non-collinear states. Based on the relation between the spin and charge currents flowing in the system and their coupling to the non-collinear magnetic configuration of the triangular trimer, we demonstrate that the DMI interaction can be significant, even in the absence of spin-orbit coupling. This is shown to emanate from the non-collinear magnetic structure, that can induce significant spin and charge currents even with spin-orbit coupling is ignored.

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Theory of noncollinear interactions beyond Heisenberg exchange: Applications to bcc Fe

Cited by 33 publications

References 31 publications

Incommensurate spin and orbital magnetism of Mn atomic chains on W(110) surface

Incommensurate spin and orbital magnetism of Mn atomic chains on W(110) surface

Exchange constants for local spin Hamiltonians from tight-binding models

First-principles Dzyaloshinskii–Moriya interaction in a non-collinear framework

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