Ion-phonon Interactions

Малкин, Б. З.

doi:10.1007/3-540-28209-2_3

Cited by 25 publications

(16 citation statements)

References 97 publications

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“…being ,respectively, the phonon frequency and the Van-Vleck coefficients. [63][64][65] The latter perform the unitary transformation from the full symmetric displacements of the ligand environments of the metal ions to the crystal normal coordinates , ν numerates the phonon modes.…”

Section: Crystal Hamiltonianmentioning

confidence: 99%

Microscopic Approach to the Problem of Cooperative Spin Crossover in Polynuclear Cluster Compounds: Application to Tetranuclear Iron(II) Square Complexes

et al. 2018

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A new microscopic approach to the problem of cooperative spin crossover in molecular crystals containing polynuclear complexes as structural units has been developed. The cooperative intercluster interaction in the crystal is shown to arise from the coupling of the molecular modes to the acoustic phonons. The interaction between ions, which belong to the same cluster, is also taken into account, that leads to interesting features in the temperature dependence of the magnetic susceptibility which are not observed in mononuclear molecular crystals. The developed general approach is adapted to the case of tetranuclear square complexes. In the latter the effect of intracluster interactions on the type of the spin transition is analyzed. The applicability of the developed approach is illustrated by the interpretation of the experimental data on the spin transition in the tetranuclear [Fe(tpa){N(CN) 2 }] 4 ⋅(BF 4) 4 ⋅(H 2 O) 2 cluster compound. For this compound the theory well reproduces the observed two-step spin transition with the plateau between the steps that corresponds to the cluster configuration with 2 high spin Fe(II) ions located along the diagonal of the square.

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Section: Crystal Hamiltonianmentioning

confidence: 99%

Microscopic Approach to the Problem of Cooperative Spin Crossover in Polynuclear Cluster Compounds: Application to Tetranuclear Iron(II) Square Complexes

et al. 2018

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“…The electron-phonon interaction in RE containing compounds originates from a modulation of the crystal field for 4f electrons by lattice vibrations [39]. In the energy range of phonons, GdFe3(BO3)4 has no electronic crystal-field states of the Gd 3+ 4f electrons.…”

Section: Coupled Electron-phonon Modesmentioning

confidence: 99%

Infrared study of lattice dynamics and spin-phonon and electron-phonon interactions in multiferroicTbFe3(BO3)4
Климин
¹
,
Kuzmenko
²
,
Kashchenko
³

et al. 2016
Phys. Rev. B
33
1
17
0
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We present a comparative far-infrared reflection spectroscopy study of phonons, phase transitions, spin-phonon and electron-phonon interactions in isostructural multiferroic iron borates of gadolinium and terbium. The behavior of phonon modes registered in a wide temperature range is consistent with a weak first-order structural phase transition (Ts = 143 for GdFe3(BO3)4 and 200 K for TbFe3(BO3)4) from high-symmetry high-temperature R32 structure into low-symmetry low-temperature P3121 one. The temperature dependences of frequencies, oscillator strengths, and damping constants of some low-frequency modes reveal an appreciable lattice anharmonicity. Peculiarities in the phonon mode behavior in both compounds at the temperature of an antiferromagnetic ordering (TN = 32 K for GdFe3(BO3)4 and 40 K for TbFe3(BO3)4) evidence the spin-phonon interaction. In the energy range of phonons, GdFe3(BO3)4 has no electronic levels but TbFe3(BO3)4 possesses several ones. We observe an onset of new bands in the excitation spectrum of TbFe3(BO3)4, due to a resonance interaction between a lattice phonon and 4f electronic crystal-field excitations of Tb 3+ . This interaction causes delocalization of the CF excitations, their Davydov splitting, and formation of coupled electron-phonon modes.

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“…The electron-phonon interaction induces ferroelectricity in many ferroelectrics [7,8] and plays an important role in the thermal and electronic conductivity of materials [9][10][11] as well as in energy dissipation in electronic devices [11][12][13]. Narrow zero-phonon spectral lines in crystals, which are useful probes of a local crystal structure and of different interactions, shift and dramatically broaden with increasing the temperature, mainly because of the electron-phonon coupling [14]. The same coupling is responsible for the crystal-field levels' relaxation and, hence, the lifetimes.…”

mentioning

confidence: 99%

“…The same coupling is responsible for the crystal-field levels' relaxation and, hence, the lifetimes. The values of these effects and of the multiphonon relaxation rates (also dependent on the electron-phonon interaction) are of primary importance for laser applications, because they influence the gain, output frequency stability, and thermal tunability of a laser [14].…”

mentioning

confidence: 99%

Bifurcations of Coupled Electron-Phonon Modes in an Antiferromagnet Subjected to a Magnetic Field

et al. 2017

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We report on a new effect caused by the electron-phonon coupling in a stoichiometric rare-earth antiferromagnetic crystal subjected to an external magnetic field, namely, the appearance of a nonzero gap in the spectrum of electronic excitations in an arbitrarily small field. The effect was registered in the low-temperature far-infrared (terahertz) reflection spectra of an easy-axis antiferromagnet PrFe 3 ðBO 3 Þ 4 in magnetic fields B ext ∥c. Both paramagnetic and magnetically ordered phases (including a spin-flop one) were studied in magnetic fields up to 30 T, and two bifurcation points were observed. We show that the field behavior of the coupled modes can be successfully explained and modeled on the basis of the equation derived in the framework of the theory of coupled electron-phonon modes, with the same field-independent electron-phonon interaction constant jWj ¼ 14.8 cm −1 .

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Ion-phonon Interactions

Cited by 25 publications

References 97 publications

Microscopic Approach to the Problem of Cooperative Spin Crossover in Polynuclear Cluster Compounds: Application to Tetranuclear Iron(II) Square Complexes

Microscopic Approach to the Problem of Cooperative Spin Crossover in Polynuclear Cluster Compounds: Application to Tetranuclear Iron(II) Square Complexes

Infrared study of lattice dynamics and spin-phonon and electron-phonon interactions in multiferroicTbFe3(BO3)4
Климин
¹
,
Kuzmenko
²
,
Kashchenko
³

et al. 2016
Phys. Rev. B
33
1
17
0
View full text Add to dashboard Cite

Bifurcations of Coupled Electron-Phonon Modes in an Antiferromagnet Subjected to a Magnetic Field

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Ion-phonon Interactions

Cited by 25 publications

References 97 publications

Microscopic Approach to the Problem of Cooperative Spin Crossover in Polynuclear Cluster Compounds: Application to Tetranuclear Iron(II) Square Complexes

Microscopic Approach to the Problem of Cooperative Spin Crossover in Polynuclear Cluster Compounds: Application to Tetranuclear Iron(II) Square Complexes

Infrared study of lattice dynamics and spin-phonon and electron-phonon interactions in multiferroicTbFe3(BO3)4Климин1, Kuzmenko2, Kashchenko3 et al. 2016Phys. Rev. B331170View full textAdd to dashboardCite

Bifurcations of Coupled Electron-Phonon Modes in an Antiferromagnet Subjected to a Magnetic Field

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Infrared study of lattice dynamics and spin-phonon and electron-phonon interactions in multiferroicTbFe3(BO3)4
Климин
¹
,
Kuzmenko
²
,
Kashchenko
³

et al. 2016
Phys. Rev. B
33
1
17
0
View full text Add to dashboard Cite