Optical phonons in MnO

Haywood, B. C.; Collins, M. F.

doi:10.1088/0022-3719/4/11/005

Cited by 44 publications

(29 citation statements)

References 11 publications

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“…Comparing Raman signals in NiO and MnO one can attribute the lowest band at 530 cm −1 to the LO mode, predicted theoretically at about 484 cm −1 in Ref. [18] or 500 cm −1 in Ref. [19].…”

Section: Resultsmentioning

confidence: 72%

Raman and infrared spectromicroscopy of manganese oxides

Миронова-Улмане

Kuzmin

Grūbe

2009

Journal of Alloys and Compounds

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Section: Resultsmentioning

confidence: 72%

Raman and infrared spectromicroscopy of manganese oxides

Миронова-Улмане

Kuzmin

Grūbe

2009

Journal of Alloys and Compounds

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“…1, we show the calculated phonon frequencies for MnO and NiO at their theoretical equilibrium geometries together with the measured data. [4][5][6][7][8] Note that for both MnO ͑Refs. 6 and 8͒ and NiO ͑Refs.…”

Section: ͑2͒mentioning

confidence: 99%

“…8 In a Letter, Savrasov and Kotliar 14 calculated the phonon frequencies of MnO and NiO by introducing a linear-response method within the framework of the localdensity approximation ͑LDA͒ and the dynamical mean-field theory ͑DMFT͒. It appears that Savrasov and Kotliar 14 only compared their calculations with the experiments by Coy et al 5 and Haywood et al 6 and did not consider the experiments for NiO by Reichardt et al 7 and for MnO by Wagner. 8 The DMFT calculations by Savrasov and Kotliar adopted the paramagnetic state for NiO, which might not be suitable to describe the room-temperature properties of NiO since the experimental Néel temperature ͑T N ͒ of NiO is 523 K, 7 and may be a reason the current calculations see such large improvements.…”

Section: ͑2͒mentioning

confidence: 99%

Broken symmetry, strong correlation, and splitting between longitudinal and transverse optical phonons of MnO and NiO from first principles

et al. 2010

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We propose a first-principles scheme, using the distorted structure, to obtain the phonons of the undistorted parent structure for systems with both broken symmetry as well as the splitting between longitudinal optical and transverse optical ͑TO͒ phonon modes due to long-range dipole-dipole interactions. Broken symmetry may result from antiferromagnetic ordering or structural distortion. Applications to the calculations of the phonon dispersions of NiO and MnO, the two benchmark Mott-Hubbard systems with the TO mode splitting for MnO, show remarkable accuracy.With advances in calculating atomic force constants within the framework of density-functional perturbation theory 1 and density-functional theory, 2 first-principles calculations can now predict electronic and vibrational properties for many classes of materials, including simple metals, transition metals, intermetallics, semiconductors, hydrides, and earth materials with exceptional accuracy. 3 However, it has been difficult to predict the lattice dynamics for strongly correlated electronic systems, particularly Mott-Hubbard insulators. These include materials such as NiO and MnO, 4-8 the La 2 CuO 4 -based cuprate superconductors, 9 and the LaMnO 3 -based colossal magnetoresistance manganites. 10 Experimental measurements also yielded inconsistent results on the frequency values of the optical phonons for both MnO ͑Refs. 6 and 8͒ and NiO. 5,7 The specific difficulties 11-15 in predicting the lattice dynamics of Mott-Hubbard insulators are: ͑i͒ the highly correlated nature of electronic states in these materials and ͑ii͒ the slight lowering of crystal symmetry as a result of antiferromagnetic ordering ͑ϳ0.6°for MnO and ϳ0.07°for NiO away from cubic 16 ͒.In this work, we report a scheme to accurately compute phonon dispersions of Mott-Hubbard systems such as MnO and NiO. This involves a combination of a method for recovering the ideal cubic symmetry from the slightly distorted structure, the mixed-space approach 17 for treating the splitting between longitudinal optical ͑LO͒ and transverse optical ͑TO͒ phonon modes, and the density-functional theory ͑DFT͒ plus U method for accounting for the strong electron correlation. 18 In applying the direct approach to predict the phonon dispersions of polar materials, a lot of effort 19-23 has been made to treat the contribution of the nonanalytical term. The mixed-space approach makes it parameter-free to accurately determine the phonon frequencies using the direct approach for polar materials. 17 In this approach, the force constants are written aswhere ⌽ ␣␤ jk is the interaction force-constant between atom j in the primitive cell M and atom k in the primitive cell P, ␣␤ jk the contribution from short-range interactions, N the number of primitive unit cells in the supercell, and D ␣␤ jk ͑na ; q → 0͒ the contribution from long-range interactions, i.e., the so-called nonanalytical part of the dynamical matrix in the limit of zero wave vector q. According to Cochran and Cowley 24

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“…In the last decades the lattice vibrations of TM monoxides have been investigated quite intensively with experimental techniques [12][13][14][15][16] . Calculations, however, have been more sparse [17][18][19][20][21][22] and, with the exception of Ref.…”

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confidence: 99%

Vibrational properties of MnO and NiO from DFT+U-based density functional perturbation theory

et al. 2011

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We introduce an extension of the density functional perturbation theory (DFPT) that allows self-consistent linear-response calculations from a DFT + U ground state. Using this scheme, the full phonon dispersion of strongly correlated materials, whose ground state can be captured with Hubbard-corrected functionals, can be accessed with unprecedented accuracy and numerical efficiency. The tool is applied to the study of MnO and NiO in their antiferromagnetic (AFII) ground state. Our results confirm the highly noncubic behavior of these systems and show a strong interplay between features of the phonon spectrum and the occupation of specific d states, suggesting the possibility to investigate the electronic structure of these materials through the analysis of their phonon spectrum

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Optical phonons in MnO

Cited by 44 publications

References 11 publications

Raman and infrared spectromicroscopy of manganese oxides

Raman and infrared spectromicroscopy of manganese oxides

Broken symmetry, strong correlation, and splitting between longitudinal and transverse optical phonons of MnO and NiO from first principles

Vibrational properties of MnO and NiO from DFT+U-based density functional perturbation theory

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