Evolution of the multiband Ruderman–Kittel–Kasuya–Yosida interaction: application to iron pnictides and chalcogenides

Akbari, Alireza; Thalmeier, Peter; Eremin, I.

doi:10.1088/1367-2630/15/3/033034

Cited by 22 publications

(24 citation statements)

References 49 publications

(94 reference statements)

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“…Both experiment and simulations suggest that Eu moments are stable even after the collapse transition. There is, however, a possibility that Eu‐Eu magnetic interactions, possibly dominated by the RKKY mechanism, get altered due to pressure effects and the ferromagnetic order is no longer the ground state. As demonstrated by the enthalpy analysis shown in Figure , the in‐plane Eu antiferromagnetic order becomes preferable in EuRbFe 4 As 4 for an intermediate pressure range, while Eu ferromagnetism is more stable in EuCsFe 4 As 4 .…”

Section: Resultsmentioning

confidence: 99%

Microscopic Modeling of Correlated Systems Under Pressure: Representative Examples

Borisov

Biswas

et al. 2019

Physica Status Solidi (b)

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The complex interplay between different order parameters in correlated systems can be finely tuned by mechanical pressure giving access to a variety of distinct phases and thereby providing new functionalities. This review addresses the challenges in the state‐of‐the‐art theoretical simulations of pressure‐induced phenomena on a few representative examples of correlated systems that are currently in the focus of on‐going contemporary research. These include organic charge‐transfer multiferroics, unconventional iron‐based superconductors, frustrated quantum magnets, and candidate systems for Kitaev physics. All these systems show pronounced structural response to moderate pressures or even structural transitions to new phases which can be successfully addressed from first principles. The simulation techniques and general trends in pressure effects are discussed for each material class.

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Section: Resultsmentioning

confidence: 99%

Microscopic Modeling of Correlated Systems Under Pressure: Representative Examples

Borisov

Biswas

et al. 2019

Physica Status Solidi (b)

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“…This idea is supported by recent dynamical mean-field theory studies of FeTe systems 27,28 showing that the Hund's coupling can promote an orbital-selective localization already in the paramagnetic phase. 29 Here, we demonstrate that the change in magnetic properties observed in the Fe 1+y Te compounds can be reasonably well captured by an effective model in which localized spins acquire a long-range RKKY-type interaction, [30][31][32] in addition to the J 1 − J 2 − J 3 Heisenberg super-exchange 14 and biquadratic couplings. [33][34][35][36][37] We note that in Refs.…”

Section: Introductionmentioning

confidence: 84%

Theory of the evolution of magnetic order inFe1+yTecompounds with increasing interstitial iron

2014

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We examine the influence of the excess of interstitial Fe on the magnetic properties of Fe1+yTe compounds. Because in iron chalcogenides the correlations are stronger than in the iron arsenides, we assume in our model that some of the Fe orbitals give rise to localized magnetic moments. These moments interact with each other via exchange interactions as well as phonon-mediated biquadratic interactions that favor a collinear double-stripe state, corresponding to the ordering vectors (±π/2, ±π/2). The remaining Fe orbitals are assumed to be itinerant, giving rise to the first-principle derived Fermi surface displaying nesting features at momenta (π, 0) / (0, π). Increasing the amount of itinerant electrons due to excess Fe, y, leads to changes in the Fermi surface and to the suppression of its nesting properties. As a result, due to the Hund's coupling between the itinerant and localized moments, increasing y leads to modifications in the local moments' exchange interactions via the multi-orbital generalization of the long-range Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. By numerically computing the RKKY corrections and minimizing the resulting effective exchange Hamiltonian, we find, in general, that the excess electrons introduced in the system change the classical magnetic ground state from a double-stripe state to an incommensurate spiral, consistent with the experimental observations. We show that these results can be understood as a result of the suppression of magnetic spectral weight of the itinerant electrons at momenta (π, 0) / (0, π), combined with the transfer of broad magnetic spectral weight from large to small momenta, promoted by the introduction of excess Fe.

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“…In fact, not only each RKKY components have strong dependence on the relative angle φ of the impurities positions, but the matrix structure of the interaction also reveals anisotropies due to either the differences between the diagonal elements I ii = I jj (i = j) or the presence of off-diagonal terms. We know that mere anisotropy in the spatial dependence of each RKKY component is not very specific to our system and it can be essentially found in other systems with anisotropic band structure [69,70]. Nevertheless, the combination of peculiar spatial dependence with the anisotropies in the matrix structure makes the RKKY coupling in TSMs far different from previously explored systems.…”

Section: Comparison To Other Systemsmentioning

confidence: 80%

Anisotropic RKKY interactions mediated by j=32 quasiparticles in half-Heusler topological semimetals

Mohammadi

Moghaddam

2020

Phys. Rev. B

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We theoretically explore the RKKY interaction mediated by spin-3/2 quasiparticles in half-Heusler topological semimetals in quasi-two-dimensional geometries. We find that while the Kohn-Luttinger terms gives rise to generalized Heisenberg coupling of the form HRKKY ∝ σ1,iIijσ2,j with a symmetric matrix Iij, addition of small antisymmetric linear spin-orbit coupling term leads to Dzyaloshinskii-Moriya (DM) coupling with an antisymmetric matrix I ij . We demonstrate that besides the oscillatory dependence on the distance, all coupling strengths strongly depend on the relative orientation of the two impurities with respect to the lattice. This yields a strongly anisotropic behavior for Iij such that by only rotating one impurity around another at a constant distance, we can see further oscillations of the RKKY couplings. This unprecedented effect is unique to our system which combines spin-orbit coupling with strongly anisotropic Fermi surfaces. We further find that all of the RKKY terms have two common features: a tetragonal warping in their map of spatial variations, and a complex beating pattern. Intriguingly, all these features survive in all dopings and we see them in both electron-and hole-doped cases. In addition, due to the lower dimensionality combined with the effects of different spin-orbit couplings, we see that only one symmetric off-diagonal term, Ixy and two DM components I xz and I yz are nonvanishing, while the remaining three off-diagonal components are identically zero. This manifests another drastic difference of RKKY interaction in half-Heusler topological semimetals compared to the electronic systems with spin-1/2 effective description. arXiv:2002.07736v1 [cond-mat.mes-hall]

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Evolution of the multiband Ruderman–Kittel–Kasuya–Yosida interaction: application to iron pnictides and chalcogenides

Cited by 22 publications

References 49 publications

Microscopic Modeling of Correlated Systems Under Pressure: Representative Examples

Microscopic Modeling of Correlated Systems Under Pressure: Representative Examples

Theory of the evolution of magnetic order inFe1+yTecompounds with increasing interstitial iron

Anisotropic RKKY interactions mediated by j=32 quasiparticles in half-Heusler topological semimetals

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