Density-functional theory and strong interactions: Orbital ordering in Mott-Hubbard insulators

Liechtenstein, A. I.; Анисимов, В. И.; Zaanen, Jan

doi:10.1103/physrevb.52.r5467

Cited by 4,282 publications

(3,113 citation statements)

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“…Both materials have the AFM 35 tetragonal <001> structure for a reasonable choice of parameters U and J. The total DOS of PuO 2 is successfully reproduced using the Liechtenstein form 16 for the Hubbard correction with the parameters U = 3.0 eV and J = 1.5 eV. However, as well as in the previous computational studies 6-9 , 40 we obtained that AFM state of PuO 2 is more stable than the experimentally observed diamagnetic state 5 .…”

Section: Discussionsupporting

confidence: 75%

Density functional theory calculations on magnetic properties of actinide compounds

Gryaznov

Heifets

Sedmidubský

2010

Phys. Chem. Chem. Phys.

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We have performed a detailed analysis of the magnetic (collinear and noncollinear) order and atomic and the electron structures of UO 2 , PuO 2 and UN on the basis of density functional theory with the Hubbard electron correlation correction (DFT+U). We have shown that the 3-k magnetic structure of UO 2 is the lowest in energy for the Hubbard parameter value of U=4.6 eV (and J=0.5 10 eV) consistent with experiments when Dudarev's formalism is used. In contrast to UO 2 , UN and PuO 2 show no trend for a distortion towards rhombohedral structure and, thus, no complex 3-k magnetic structure is to be anticipated in these materials.

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Section: Discussionsupporting

confidence: 75%

Density functional theory calculations on magnetic properties of actinide compounds

Gryaznov

Heifets

Sedmidubský

2010

Phys. Chem. Chem. Phys.

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“…The +U is essentially chosen to act as an on-site correction to reproduce the Coulomb interaction, thus acting as a penalty to delocalisation. Two popular methods are those derived by Liechtenstein 10 and Dudarev. 4 Of these, the latter is the more widely used due to its simplicity.…”

Section: Introductionmentioning

confidence: 99%

Occupation matrix control of d- and f-electron localisations using DFT + U

Allen

Watson

2014

Phys. Chem. Chem. Phys.

201

200

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The use of a density functional theory methodology with on-site corrections (DFT + U) has been repeatedly shown to give an improved description of localised d and f states over those predicted with a standard DFT approach. However, the localisation of electrons also carries with it the problem of metastability, due to the possible occupation of different orbitals and different locations. This study details the use of an occupation matrix control methodology for simulating localised d and f states with a plane-wave DFT + U approach which allows the user to control both the site and orbital localisation.This approach is tested for orbital occupation using octahedral and tetrahedral Ti(III) and Ce(III) carbonyl clusters and for orbital and site location using the periodic systems anatase-TiO 2 and CeO 2 . The periodic cells are tested by the addition of an electron and through the formation of a neutral oxygen vacancy (leaving two electrons to localise). These test systems allow the successful study of orbital degeneracies, the presence of metastable states and the importance of controlling the site of localisation within the cell, and it highlights the use an occupation matrix control methodology can have in electronic structure calculations.

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“…[25] On-site Coulomb interaction is included in the mean-field, rotationally invariant GGA+U approach with U − J = 2 eV for Cr 3d orbitals. [22,26] A plane-wave cutoff of 520 eV is used. The valence includes 12 electrons for Cr (3p 6 3d 5 4s 1 ), 12 for Ti (3s 2 3p 6 3d 2 4s 2 ) and 6 for O (2s 2 2p 4 ).…”

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Single-Spin Dirac Fermion and Chern Insulator Based on Simple Oxides

et al. 2015

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It is highly desirable to combine recent advances in the topological quantum phases with technologically relevant materials. Chromium dioxide (CrO2) is a half-metallic material, widely used in high-end data storage applications. Using first principles calculations, we show via interfacial orbital design that a novel class of half semi-metallic Dirac electronic phase emerges at the interface CrO2 with TiO2 in both thin film and superlattice configurations, with four spin-polarized Dirac points in momentum-space (k-space) band structure. When the spin and orbital degrees of freedom are allowed to couple, the CrO2/TiO2 superlattice becomes a Chern insulator without external fields or additional doping. With topological gaps equivalent to 43 Kelvin and a Chern number 2, the ensuing quantization of Hall conductance to 2e 2 /h will enable potential development of these highly industrialized oxides for applications in topologically high fidelity data storage and energy-efficient electronic and spintronic devices.The defining feature of massless Dirac Fermions [1,2] is the linear energy dispersion, implying that a quasiparticle moves at a constant speed independent of its energy, as governed by relativistic quantum mechanics. The exploration of novel Dirac materials with bulk Dirac or Dirac-Weyl states remains a great challenge in condensed matter and materials physics. [3][4][5][6][7][8][9][10] In particular, there has yet been neither theoretical proposal nor observation of materials systems with Dirac points a single spin species, which may be called a half-semimetal. Half metals are a class of ferromagnetic materials in which the conduction is dominated by one spin component while the other spin is gapped, which stands to enable reduced device size and non-volatile memory. At a rudimentary level, a half semi-metal will harbour the fascinating Dirac physics [1][2][3][4][5][6][7][8][9][10] all with a single spin. And as a not-so-trivial consequence, it may lead to Chern insulators [11][12][13][14] or valleytronics materials [15][16][17][18] when the low-energy excitations turn massive. In particular, a Chern insulator exhibits quantum anomalous Hall (QAH) effect in the absence of external magnetic field. This important fundamental phenomenon was established experimentally recently in magnetically doped topological insulator. [14] A spontaneous half semimetal will lead to a Chern insulator with appropriate spin-orbit coupling (SOC) and symmetry, which is advantageous for it requires no addition of impurity to the system. Precisely controlled growth of heterojunctions of oxides offers a unique avenue for exploring novel interfacial quantum phases, in which the interplay of orbital, charge, spin and lattice degrees of freedom gives rise to remarkably rich chemical, structural, electronic and magnetic varieties. Bulk CrO 2 (structure shown in Fig. 1) is a robust half metal even at elevated temperatures, [19][20][21] and widely used in enterprisegrade data storage. Here, we consider the possibility to fashion the CrO 2 int...

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Density-functional theory and strong interactions: Orbital ordering in Mott-Hubbard insulators

Cited by 4,282 publications

References 3 publications

Density functional theory calculations on magnetic properties of actinide compounds

Density functional theory calculations on magnetic properties of actinide compounds

Occupation matrix control of d- and f-electron localisations using DFT + U

Single-Spin Dirac Fermion and Chern Insulator Based on Simple Oxides

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