Charge density functional plus 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>U</mml:mi></mml:math>
 theory of 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>LaMnO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math>
: Phase diagram, electronic structure, and magnetic interaction

Jang, Seung Woo; Ryee, Siheon; Yoon, Hongkee; Han, Myung Joon

doi:10.1103/physrevb.98.125126

Cited by 22 publications

(7 citation statements)

References 101 publications

(141 reference statements)

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“…Thus, there is no intrinsic magnetism of the ligand (halide) states, which, on the contrary, appears in sDFT(+U ) case. DFT + U and sDFT + U have been previously shown to produce substantially different results for the total energies [52][53][54][55] and the exchange interaction parameters [56]. As was mentioned above, the magnetism of ligands is particularly important in CrX 3 systems, which motivated us to compare the results obtained with these two flavors of +U methods.…”

Section: A Electronic Structurementioning

confidence: 98%

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

et al. 2020

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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.

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Section: A Electronic Structurementioning

confidence: 98%

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

et al. 2020

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“…In detail, J ij is estimated as a response to small spin tiltings (as a perturbation) from the given converged solution, as shown the detailed formulation in [37][38][39]. More application examples of OpenMX in calculating Heisenberg exchange parameters are reported by the OpenMX's developers in the literature [38][39][40][41]. In fact, the unit cell here is already very large and thus the lattice translation vectors have negligible influence on the calculated J ij .…”

Section: The Constant Term In H Cfmentioning

confidence: 99%

Calculating temperature-dependent properties of Nd2Fe14B permanent magnets by atomistic spin model simulations

Gong

Evans

et al. 2019

Phys. Rev. B

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Temperature-dependent magnetic properties of Nd2Fe14B permanent magnets, i.e., saturation magnetization Ms(T ), effective magnetic anisotropy constants K eff i (T ) (i = 1, 2, 3), domain wall width δw(T ), and exchange stiffness constant Ae(T ), are calculated by using ab-initio informed atomistic spin model simulations. We construct the atomistic spin model Hamiltonian for Nd2Fe14B by using the Heisenberg exchange of Fe−Fe and Fe−Nd atomic pairs, the uniaxial single-ion anisotropy of Fe atoms, and the crystal-field energy of Nd ions which is approximately expanded into an energy formula featured by second, fourth, and sixth-order phenomenological anisotropy constants. After applying a temperature rescaling strategy, we show that the calculated Curie temperature, spin-reorientation phenomenon, Ms(T ), δw(T ), and K eff i (T ) agree well with the experimental results. Ae(T ) is estimated through a general continuum description of the domain wall profile by mapping atomistic magnetic moments to the macroscopic magnetization. Ae is found to decrease more slowly than K eff 1 with increasing temperature, and approximately scale with normalized magnetization as Ae(T ) ∼ m 1.2 . Especially, the possible domain wall configurations at temperatures below the spin-reorientation temperature and the associated δw and Ae are identified. This work provokes a scale bridge between ab-initio calculations and temperature-dependent micromagnetic simulations of Nd-Fe-B permanent magnets.

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“…Here we first estimate the interaction parameters based on the most advanced scheme, namely, cRPA [56,57] which is computationally demanding but known as quite reliable [68][69][70][71][72]. The calculated on-site Coulomb repulsion U = 2.0 eV for the bulk CrI 3 and U = 2.9 eV for monolayer.…”

mentioning

confidence: 99%

Microscopic understanding of magnetic interactions in bilayer CrI3

Jang

Jeong

Yoon

et al. 2019

Phys. Rev. Materials

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We performed a detailed microscopic analysis of the inter-layer magnetic couplings for bilayer CrI3. As the first step toward understanding the recent experimental observations and utilizing them for device applications, we estimated magnetic force response as well as total energy. Various van der Waals functionals unequivocally point to the ferromagnetic ground state for the low-temperature structured bilayer CrI3 which is further confirmed independently by magnetic force response calculations. The calculated orbital-dependent magnetic forces clearly show that eg-t2g interaction is the key to stabilize this ferromagnetic order. By suppressing this ferromagnetic interaction and enhancing antiferromagnetic orbital channels of eg-eg and t2g-t2g, one can realize the desirable antiferromagnetic order. We showed that high-temperature monoclinic stacking can be the case. Our results provide unique information and insight to understand the magnetism of multi-layer CrI3 paving the way to utilize it for applications.

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Charge density functional plus U theory of LaMnO3 : Phase diagram, electronic structure, and magnetic interaction

Cited by 22 publications

References 101 publications

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

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

Calculating temperature-dependent properties of Nd2Fe14B permanent magnets by atomistic spin model simulations

Microscopic understanding of magnetic interactions in bilayer CrI3

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