Raman, Infrared and Optical Spectra of the Spin-Peierls Compound NaV2O5

Golubchik, S. A.; Isobe, Masahiko; Ivlev, A.N.; Mavrin, B. N.; Попова, М. Н.; Sushkov, A. B.; Ueda, Yutaka; Васильев, А. Н.

doi:10.1143/jpsj.66.4042

Cited by 67 publications

(76 citation statements)

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“…4 In α'-NaV 2 O 5 a similar broad Raman mode is found at around 650 cm −1 in aa polarization. 17,18,19,20,21,22 Several scenarios have been proposed to explain this broad Gaussian-like band: (i) electric dipole transitions between the crystal field split V 3d levels, (ii) magnon scattering, and (iii) a mode due to strong electron-phonon coupling. Up to now, a consensus has not been reached on this issue.…”

Section: Resultsmentioning

confidence: 99%

Pressure-induced changes in the optical properties of quasi-one-dimensionalβ−Na0.33V2O5

et al. 2007

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The pressure-induced changes in the optical properties of β-Na0.33V2O5 single crystals at room temperature were studied by polarization-dependent Raman and far-infrared reflectivity measurements under high pressure. From the changes in the Raman-and infrared-active phonon modes in the pressure range 9 -12 GPa a transfer of charge between the different V sites can be inferred. The importance of electron-phonon coupling in the low-pressure regime is discussed.

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Section: Resultsmentioning

confidence: 99%

Pressure-induced changes in the optical properties of quasi-one-dimensionalβ−Na0.33V2O5

et al. 2007

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“…The most interesting feature of the xx component (light polarized along the rungs) is a strong peak at 1.03 eV in agreement with experiment. 16,41,42 An analysis of the interband momentum matrix elements at different electron wavevectors k y shows that the first peak in the xx response arises due to transitions between the bonding and antibonding band states within one V rung. The energy of the peak is larger than 2t ⊥ because of the band dispersion along the y axis and can be estimated to be 2(t ⊥ +t ), which is 1.12 eV.…”

Section: Dielectric Functionmentioning

confidence: 99%

Optical properties, electron-phonon coupling, and Raman scattering of vanadium ladder compounds

et al. 2004

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The electronic structure of two V-based ladder compounds, the quarter-filled NaV2O5 in the symmetric phase and the iso-structural half-filled CaV2O5, is investigated by ab initio calculations. Based on the bandstructure we determine the dielectric tensor ε(ω) of these systems in a wide energy range. The frequencies and eigenvectors of the fully symmetric Ag phonon modes and the corresponding electron-phonon and spin-phonon coupling parameters are also calculated from firstprinciples. We determine the Raman scattering intensities of the Ag phonon modes as a function of polarization and frequency of the exciting light. All results, i.e. shape and magnitude of the dielectric function, phonon frequencies and Raman intensities show very good agreement with available experimental data.

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“…According to DFC's, the vanadium d-level degeneracy is removed due to anisotropy of the crystal field [25] and the lowest occupied 3d xy states are separated by 1-5 eV from remaining 3d states. This energy scale provoked the assignment of 0.9 eV peak in the optical spectra, Fig.2, as a transition between d-d crystal-field levels of vanadium ions [15]. However, recent work on Ca-doped NaV 2 O 5 showed that 0.9 eV peak decreases in intensity with increasing Ca, [26] This result seams to be inconsistent with the d-d transition picture (the d-d transition intensity should be proportional to the number of V 4+ ions).…”

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confidence: 94%

“…In these studies, the various charge-ordering ground states were proposed for the low-temperature phase of NaV 2 O 5 . These concepts were tested by comparison with optical conductivity data [14][15][16] with some success, but no consistent picture has yet emerged. These concepts were tested by comparison with optical conductivity data [14][15][16][17] with some success but no consistent picture has emerged yet.…”

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confidence: 99%

“…These concepts were tested by comparison with optical conductivity data [14][15][16] with some success, but no consistent picture has yet emerged. These concepts were tested by comparison with optical conductivity data [14][15][16][17] with some success but no consistent picture has emerged yet. None of the models proposed to date have reproduced optical transitions in the 0.8-5.5 eV range and provided an explanation for the origin of the low-frequency excitations (observed in both IR and Raman spectra) [14,9].…”

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Charge ordering and optical transitions ofLiV2O5and
Konstantinović
¹
,
Dong
²
,
Ziaei
³

et al. 2001
Phys. Rev. B
12
1
13
0
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We present measurements of the polarized optical spectra of NaV 2 O 5 and LiV 2 O 5 . In an energy range from 0.5 to 5.5 eV, we observe similar peaks in the E a spectra of NaV 2 O 5 and LiV 2 O 5 , which suggests similar electronic structures along the a axis in both materials. On the other hand, we find an almost complete suppression of the peaks in σ b of LiV 2 O 5 around 1 and 5 eV. We attribute this suppression to the charge localization effect originating from the existence of a double-chain charge-ordering pattern in LiV 2 O 5 . : 78.40.-q, 71.35.-y, 75.50.-y In the past several years, quantum phenomena resulting from the low dimensionality of effective electron interactions in solids have been investigated with increasing intensity from both experimental and theoretical points of view. The increase in interest was partially motivated by the discovery of inorganic materials which exhibit quantum effects, such as the PACS, and by a common belief that these studies would give us a better understanding of electron correlations in general.The vanadate family of AV 2 O 5 oxides have demonstrated a variety of the low-dimensional phenomena which originate from their peculiar crystal structures [3]. These oxides are quasi two-dimensional (2D) materials with layers formed by V O 5 square pyramids. The A atoms are situated between layers as intercalants, but in fact they determine the valence state of vanadium atoms (acting as charge reservoirs). If the A atoms belong to the first column in the periodic table, such as A = Li, Na, each valence electron is shared between two vanadium atoms. As a result the V ions are in a mixed valence-state with an average valence of +4.5. The common consequence of mixed valence in these structures is the appearance of a quasi-1D magnetic interaction, since chains carrying the spin (made of V 4+ , S=1/2) are separated from each other by nonmagnetic chains (V 5+ ). In both LiV 2 O 5 and NaV 2 O 5 the 1D character of the magnetic ordering was confirmed [4,5]. In addition, there is a possibility of the existence of strong valence fluctuations, and eventually charge ordering (CO) effects.

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Raman, Infrared and Optical Spectra of the Spin-Peierls Compound NaV₂O₅

Cited by 67 publications

References 9 publications

Pressure-induced changes in the optical properties of quasi-one-dimensionalβ−Na0.33V2O5

Pressure-induced changes in the optical properties of quasi-one-dimensionalβ−Na0.33V2O5

Optical properties, electron-phonon coupling, and Raman scattering of vanadium ladder compounds

Charge ordering and optical transitions ofLiV2O5and
Konstantinović
¹
,
Dong
²
,
Ziaei
³

et al. 2001
Phys. Rev. B
12
1
13
0
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Raman, Infrared and Optical Spectra of the Spin-Peierls Compound NaV2O5

Cited by 67 publications

References 9 publications

Pressure-induced changes in the optical properties of quasi-one-dimensionalβ−Na0.33V2O5

Pressure-induced changes in the optical properties of quasi-one-dimensionalβ−Na0.33V2O5

Optical properties, electron-phonon coupling, and Raman scattering of vanadium ladder compounds

Charge ordering and optical transitions ofLiV2O5andKonstantinović1, Dong2, Ziaei3 et al. 2001Phys. Rev. B121130View full textAdd to dashboardCite

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Raman, Infrared and Optical Spectra of the Spin-Peierls Compound NaV₂O₅

Charge ordering and optical transitions ofLiV2O5and
Konstantinović
¹
,
Dong
²
,
Ziaei
³

et al. 2001
Phys. Rev. B
12
1
13
0
View full text Add to dashboard Cite