Calculating condensed matter properties using the KKR-Green's function method—recent developments and applications

Ebert, H.; Ködderitzsch, D.; Minář, J.

doi:10.1088/0034-4885/74/9/096501

Cited by 997 publications

(721 citation statements)

References 461 publications

(758 reference statements)

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“…The effective exchange interactions between adjacent metal atoms in the ground state magnetic structures were evaluated using the spin-polarized, relativistic Korringa−Kohn−Rostoker (SPRKKR) package. 27 The effective intersite exchange parameters, J ij , between sites i and j are obtained from the effective Heisenberg Hamiltonian,…”

Section: Computational Detailsmentioning

confidence: 99%

Magnetic Ordering in Tetragonal 3d Metal Arsenides M₂As (M = Cr, Mn, Fe): An Ab Initio Investigation

2013

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The electronic and magnetic structures of the tetragonal Cu 2 Sb-type 3d metal arsenides (M 2 As, M = Cr, Mn, Fe) were examined using density functional theory to identify chemical influences on their respective patterns of magnetic order. Each compound adopts a different antiferromagnetic (AFM) ordering of local moments associated with the 3d metal sites, but every one involves a doubled crystallographic c-axis. These AFM ordering patterns are rationalized by the results of VASP calculations on several magnetically ordered models using a × a × 2c supercell. Effective exchange parameters obtained from SPRKKR calculations indicate that both direct and indirect exchange couplings play essential roles in understanding the different magnetic orderings observed. The nature of nearest-neighbor direct exchange couplings, that is, either ferromagnetic (FM) or AFM, were predicted by analysis of the corresponding crystal orbital Hamilton population (COHP) curves obtained by TB-LMTO calculations. Interestingly, the magnetic structures of Fe 2 As and Mn 2 As show tetragonal symmetry, but a magnetostrictive tetragonal-to-orthorhombic distortion could occur in Cr 2 As through AFM Cr1-Cr2 coupling between symmetry inequivalent Cr atoms along the a-axis, but FM coupling along the b-axis. A LSDA+U approach is required to achieve magnetic moment values for Mn 2 As in better agreement with experimental values, although computations always predict the moment at the M1 site to be lower than that at the M2 site. Finally, a rigid-band model applied to the calculated DOS curve of Mn 2 As correctly assesses the magnetic ordering patterns in Cr 2 As and Fe 2 As. ABSTRACT: The electronic and magnetic structures of the tetragonal Cu 2 Sb-type 3d metal arsenides (M 2 As, M = Cr, Mn, Fe) were examined using density functional theory to identify chemical influences on their respective patterns of magnetic order. Each compound adopts a different antiferromagnetic (AFM) ordering of local moments associated with the 3d metal sites, but every one involves a doubled crystallographic c-axis. These AFM ordering patterns are rationalized by the results of VASP calculations on several magnetically ordered models using a × a × 2c supercell. Effective exchange parameters obtained from SPRKKR calculations indicate that both direct and indirect exchange couplings play essential roles in understanding the different magnetic orderings observed. The nature of nearest-neighbor direct exchange couplings, that is, either ferromagnetic (FM) or AFM, were predicted by analysis of the corresponding crystal orbital Hamilton population (COHP) curves obtained by TB-LMTO calculations. Interestingly, the magnetic structures of Fe 2 As and Mn 2 As show tetragonal symmetry, but a magnetostrictive tetragonal-to-orthorhombic distortion could occur in Cr 2 As through AFM Cr1−Cr2 coupling between symmetry inequivalent Cr atoms along the a-axis, but FM coupling along the b-axis. A LSDA+U approach is required to achieve magnetic moment values for Mn 2 As in better agree...

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Section: Computational Detailsmentioning

confidence: 99%

Magnetic Ordering in Tetragonal 3d Metal Arsenides M₂As (M = Cr, Mn, Fe): An Ab Initio Investigation

2013

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“…[9][10][11] The MFT proved to be a powerful method for studying magnetic interactions from first principles. [12][13][14][15][16] The necessity of only a single magnetic state allows to study the applicability of the Heisenberg model by determining the dependence of the exchange interactions on the magnetic states.…”

Section: Introductionmentioning

confidence: 99%

Exchange interactions in transition metal oxides: the role of oxygen spin polarization

Logemann¹,

Руденко²,

Katsnelson³

et al. 2017

J. Phys.: Condens. Matter

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Abstract. Magnetism of transition metal (TM) oxides is usually described in terms of the Heisenberg model, with orientation-independent interactions between the spins. However, the applicability of such a model is not fully justified for TM oxides because spin polarization of oxygen is usually ignored. In the conventional model based on the Anderson principle, oxygen effects are considered as a property of the TM ion and only TM interactions are relevant. Here, we perform a systematic comparison between two approaches for spin polarization on oxygen in typical TM oxides. To this end, we calculate the exchange interactions in NiO, MnO, and hematite (Fe 2 O 3 ) for different magnetic configurations using the magnetic force theorem. We consider the full spin Hamiltonian including oxygen sites, and also derive an effective model where the spin polarization on oxygen renormalizes the exchange interactions between TM sites. Surprisingly, the exchange interactions in NiO depend on the magnetic state if spin polarization on oxygen is neglected, resulting in non-Heisenberg behavior. In contrast, the inclusion of spin polarization in NiO makes the Heisenberg model more applicable. Just the opposite, MnO behaves as a Heisenberg magnet when oxygen spin polarization is neglected, but shows strong non-Heisenberg effects when spin polarization on oxygen is included. In hematite, both models result in non-Heisenberg behavior. General applicability of the magnetic force theorem as well as the Heisenberg model to TM oxides is discussed.

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“…This is in contrast to the simpler three-step model where ionization is divided into three separate processes 15 . These approaches, largely based on many-body perturbation theory formulated in terms of Green's function, proved to be successful in many relevant cases [16][17][18][19] . However the perturbative approach underlying these methods is not suitable to describe tARPES.…”

Section: Introductionmentioning

confidence: 99%

A First-Principles Time-Dependent Density Functional Theory Framework for Spin and Time-Resolved Angular-Resolved Photoelectron Spectroscopy in Periodic Systems

Giovannini

Hübener

Rubio

2016

J. Chem. Theory Comput.

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We present a novel theoretical approach to simulate spin, time and angular-resolved photoelectron spectroscopy (ARPES) from first principles that is applicable to surfaces, thin films, few layer systems, and low-dimensional nanostructures. The method is based on a general formulation in the framework of time-dependent density functional theory (TDDFT) to describe the real timeevolution of electrons escaping from a surface under the effect of any external (arbitrary) laser field. By extending the so called t-SURFF method to periodic systems one can calculate the final photoelectron spectrum by collecting the flux of the ionization current trough an analysing surface. The resulting approach, that we named t-SURFFP, allows to describe a wide range of irradiation conditions without any assumption on the dynamics of the ionization process allowing for pumpprobe simulations on an equal footing. To illustrate the wide scope of applicability of the method we present applications to graphene, mono-and bi-layer WSe2, and hexagonal BN under different laser configurations.

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Calculating condensed matter properties using the KKR-Green's function method—recent developments and applications

Cited by 997 publications

References 461 publications

Magnetic Ordering in Tetragonal 3d Metal Arsenides M₂As (M = Cr, Mn, Fe): An Ab Initio Investigation

Magnetic Ordering in Tetragonal 3d Metal Arsenides M₂As (M = Cr, Mn, Fe): An Ab Initio Investigation

Exchange interactions in transition metal oxides: the role of oxygen spin polarization

A First-Principles Time-Dependent Density Functional Theory Framework for Spin and Time-Resolved Angular-Resolved Photoelectron Spectroscopy in Periodic Systems

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Calculating condensed matter properties using the KKR-Green's function method—recent developments and applications

Cited by 997 publications

References 461 publications

Magnetic Ordering in Tetragonal 3d Metal Arsenides M2As (M = Cr, Mn, Fe): An Ab Initio Investigation

Magnetic Ordering in Tetragonal 3d Metal Arsenides M2As (M = Cr, Mn, Fe): An Ab Initio Investigation

Exchange interactions in transition metal oxides: the role of oxygen spin polarization

A First-Principles Time-Dependent Density Functional Theory Framework for Spin and Time-Resolved Angular-Resolved Photoelectron Spectroscopy in Periodic Systems

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Magnetic Ordering in Tetragonal 3d Metal Arsenides M₂As (M = Cr, Mn, Fe): An Ab Initio Investigation

Magnetic Ordering in Tetragonal 3d Metal Arsenides M₂As (M = Cr, Mn, Fe): An Ab Initio Investigation