Temperature dependence of Raman scattering and anharmonicity study of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">MgF</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Perakis, A.; Sarantopoulou, E.; Raptis, Y. S.; Raptis, Constantine A.

doi:10.1103/physrevb.59.775

Cited by 28 publications

(22 citation statements)

References 27 publications

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“…However, further support for this viewpoint comes from a recent thorough analysis of the B 1g phonon temperature and pressure dependence in isostructural MgF 2 . This study has confirmed that the anomalous mode softening observed with decreasing temperature in this compound is indeed caused by the thermal contraction of the lattice [21].…”

Section: B 1g Mode Softeningsupporting

confidence: 79%

Spin–phonon interaction and mode softening in NiF2

Lockwood

2002

Low Temperature Physics

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The temperature dependence of the four Raman-active phonons in NiF 2 has been investigated at temperatures above and below the antiferromagnetic ordering temperature of T N = 73 K. All four modes exhibit distinct anomalies in their intensities and frequencies near T N due to spin-phonon coupling. The phonon linewidths also exhibit weak anomalies. From the temperature dependences of the phonon frequencies, estimates are made of the spin-phonon coupling coefficients. The B 1g phonon exhibits anomalous mode softening with decreasing temperature from 300 K to T N .

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Section: B 1g Mode Softeningsupporting

confidence: 79%

Spin–phonon interaction and mode softening in NiF2

Lockwood

2002

Low Temperature Physics

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“…Its frequency changes little with temperature, but softens with pressure. Studies on other materials with the rutile structure, e.g., SnO 2 , MgF 2 and FeF 2 report similar behavior of the B 1g mode [17][18][19][20] . There are two conflicting views on the physical origin of these anomalies.…”

mentioning

confidence: 73%

“…The success of the MD calculations at elevated temperature and pressure shows that a shell model with a Buckingham potential can reproduce both the anomalous quasiharmonicity and the explicit anharmonicity of the B 1g mode of rutile TiO 2 , giving a detailed picture than can be compared to results from uniaxial-stress experiments 49 , zero-pressure extrapolations of phonon frequencies 19,20 , and DFT calculations within the quasiharmonic approximation 22 . No orthorhombic or other distortion was found for our supercell at any temperature or pressure.…”

Section: B Anharmonicities From MD Simulationsmentioning

confidence: 99%

“…There are two conflicting views on the physical origin of these anomalies. One attributes it to an incipient structural phase transition 17,21,22 , and the other attributes it to a thermal-or pressure-induced lattice contraction [18][19][20] . Lattice dynamics calculations based on density functional theory (DFT) were used to study the effect of pressure on phonons in rutile TiO 2 22,23 .…”

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confidence: 99%

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Phonon anharmonicity of rutile TiO2studied by Raman spectrometry and molecular dynamics simulations

2012

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Raman spectra of rutile titanium dioxide (TiO 2 ) were measured at temperatures from 100 K to 1150 K. Each Raman mode showed unique changes with temperature. Beyond the volume-dependent quasiharmonicity, the explicit anharmonicity was large. A new method was developed to fit the thermal broadenings and shifts of Raman peaks with a full calculation of the kinematics of 3-phonon and 4-phonon processes, allowing the cubic and quartic components of the anharmonicity to be identified for each Raman mode. A dominant role of phonon-phonon kinematics on phonon shifts and broadenings is reported. Force field molecular dynamics (MD) calculations with the Fourier-transformed velocity autocorrelation method were also used to perform a quantitative study of anharmonic effects, successfully accounting for the anomalous phonon anharmonicity of the B 1g mode.

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“…It has been shown for MgF 2 [16] that taking into account lower symmetry effects changes this contribution by 5-15%. Taking into account the experimental data of the unit cell volume obtained from synchrotron powder diffraction [5] …”

Section: Methodsmentioning

confidence: 99%

Lattice anharmonicity and structural evolution of LiBH₄: an insight from Raman and X-ray diffraction experiments

Hagemann

Filinchuk²,

Chernyshov³

et al. 2009

Phase Transitions

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New in situ Raman and synchrotron X-ray diffraction data (between 300 and 400 K) in conjunction with separate temperature-dependent Raman data (between 7 and 400 K) are presented. The low-frequency Raman spectra show good agreement with theoretical values obtained previously using periodic DFT calculations. The temperature-dependent spectra reveal the presence of significant anharmonicity of librational modes neither predicted theoretically nor noted in previous experiments. The splitting of the internal deformation mode 2 (of E symmetry in the free ion) decreases continuously with increasing temperature, but drops abruptly at the first-order orthorhombic to hexagonal phase transition observed at 381 K. The temperature dependence of the linewidth of the internal deformation mode 2 reveals coupling to reorientational motions of the borohydride ion in the orthorhombic phase. The thermal evolution of both crystal structure and vibration frequencies agree with the phase diagram suggested by the Landau theory.

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Temperature dependence of Raman scattering and anharmonicity study ofMgF2

Cited by 28 publications

References 27 publications

Spin–phonon interaction and mode softening in NiF2

Spin–phonon interaction and mode softening in NiF2

Phonon anharmonicity of rutile TiO2studied by Raman spectrometry and molecular dynamics simulations

Lattice anharmonicity and structural evolution of LiBH₄: an insight from Raman and X-ray diffraction experiments

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Temperature dependence of Raman scattering and anharmonicity study ofMgF2

Cited by 28 publications

References 27 publications

Spin–phonon interaction and mode softening in NiF2

Spin–phonon interaction and mode softening in NiF2

Phonon anharmonicity of rutile TiO2studied by Raman spectrometry and molecular dynamics simulations

Lattice anharmonicity and structural evolution of LiBH4: an insight from Raman and X-ray diffraction experiments

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Lattice anharmonicity and structural evolution of LiBH₄: an insight from Raman and X-ray diffraction experiments