Phonon dispersion in NiO

Coy, R.A.; Tompson, C. W.; Gürmen, E.

doi:10.1016/0038-1098(76)90220-9

Cited by 81 publications

(26 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Wagner et al 8 pointed out that their room-temperature phonon dispersions for MnO measured for a flame-grown single crystal of 4 cm 3 using a three-axis crystal spectrometer were more reliable than the measurement by Haywood and Collins 6 who used a small pillar about 5 mm 2 by 2 cm and a beryllium filter technique, which inherently has low q-space resolution. For NiO, both measurements by Reichardt et al 7 and Coy et al 5 were performed using three-axis crystal spectrometers at room temperature. However, the measured data by Reichardt et al have been more widely cited than those by Coy et al Our calculated results strongly support the frequently cited experiments for NiO by Reichardt et al 7 and for MnO by Wagner et al 8 The calculated phonon dispersions of MnO by Wdowik and Legut 15 and the calculated phonon dispersions of NiO by Savrasov and Kotliar 14 are also plotted in Fig.…”

Section: ͑2͒mentioning

confidence: 99%

“…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%

“…6 and 8͒ and NiO. 5,7 The specific difficulties [11][12][13][14][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 ͒.…”

mentioning

confidence: 99%

See 2 more Smart Citations

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

et al. 2010

View full text Add to dashboard Cite

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

show abstract

Section: ͑2͒mentioning

confidence: 99%

Section: ͑2͒mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

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

et al. 2010

View full text Add to dashboard Cite

show abstract

“…[51] indicated that they did not expect large effects of the magnetic transition on the phonon spectrum of NiO, besides a general temperatureinduced softening with lattice frequencies reduced typically by about 3%. This conclusion is generally supported by good agreement that can be seen for acoustic branches of the phonon spectrum between our calculations for the PM NiO and Coy et al [51] measurements for the AFM samples. On the other hand, our paramagnetic optical dispersion relations differ from the experimental AFM ones to a larger degree.…”

Section: Phonon Dispersion Relationsmentioning

confidence: 99%

“…However, the phonon spectra of the AFM NiO phase were measured by Coy et al [51] at 297 K. They observed a well-defined band gap of approximately 1.6 THz. In addition, Coy et al mentioned the preliminary measurements above the Néel temperature at 600 K. The authors of Ref.…”

Section: Phonon Dispersion Relationsmentioning

confidence: 99%

Effect of the lattice dynamics on the electronic structure of paramagnetic NiO within the disordered local moment picture

et al. 2018

View full text Add to dashboard Cite

Using the disordered local moments approach in combination with the ab initio molecular dynamics method, we simulate the behavior of a paramagnetic phase of NiO at finite temperatures to investigate the effect of magnetic disorder, thermal expansion, and lattice vibrations on its electronic structure. In addition, we study its lattice dynamics. We verify the reliability of our theoretical scheme via comparison of our results with available experiment and earlier theoretical studies carried out within static approximations. We present the phonon dispersion relations for the paramagnetic rock-salt (B1) phase of NiO and demonstrate that it is dynamically stable. We observe that including the magnetic disorder to simulate the paramagnetic phase has a small yet visible effect on the band gap. The amplitude of the local magnetic moment of Ni ions from our calculations for both antiferromagnetic and paramagnetic phases agree well with other theoretical and experimental values. We demonstrate that the increase of temperature up to 1000 K does not affect the electronic structure strongly. Taking into account the lattice vibrations and thermal expansion at higher temperatures have a major impact on the electronic structure, reducing the band gap from ∼3.5 eV at 600 K to ∼2.5 eV at 2000 K. We conclude that static lattice approximations can be safely employed in simulations of the paramagnetic state of NiO up to relatively high temperatures (∼1000 K), but as we get closer to the melting temperature vibrational effects become quite large and therefore should be included in the calculations.

show abstract

Magnetic Interactions in the Cubic Mott InsulatorsNiO,MnO, andCoOand the Related OxidesCuOandFeO

Lockwood

Cottam

2021

Oxide Electronics

View full text Add to dashboard Cite

Phonon dispersion in NiO

Cited by 81 publications

References 15 publications

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

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

Effect of the lattice dynamics on the electronic structure of paramagnetic NiO within the disordered local moment picture

Magnetic Interactions in the Cubic Mott InsulatorsNiO,MnO, andCoOand the Related OxidesCuOandFeO

Contact Info

Product

Resources

About