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Long, Van Cao; Zhu, Zhangxiang; Musfeldt, J. L.; Wei, Xing; Koo, Hyun‐Joo; Whangbo, Myung Hwan; Jegoudez, J.; Revcolevschi, A.

doi:10.1103/physrevb.60.15721

Cited by 27 publications

(46 citation statements)

References 44 publications

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“…5c and 5d). Our experimental spectra agree well with the previous results derived from reflectivity 17,18 and absorption 16 measurements of α ′ -NaV 2 O 5 . Comparing σ xx with the q a experimental data (Figs.…”

Section: Optical Conductivitysupporting

confidence: 90%

“…The electronic structure of α ′ -NaV 2 O 5 has been intensively studied experimentally by means of optical absorption 16 and reflectivity, 17,18 as well as theoretically within the framework of bandstructure calculations 3,[19][20][21] and exact diagonalization techniques. [22][23][24] Nevertheless, there is a controversial discussion about the origin of the electronic excitations in this system.…”

Section: Introductionmentioning

confidence: 99%

“…[22][23][24] Nevertheless, there is a controversial discussion about the origin of the electronic excitations in this system. For example, concerning the absorption peak occurring at about 1 eV in optics, transitions between bonding and antibonding combinations of V 3d xy states, 3,17,25 transitions between vanadium states of different symmetry 18 as well as on-site d − d transitions between crystal-field-split vanadium 3d states 16 have been proposed as the origin of this feature. Furthermore, the information from the experiments still appears to be insufficient to enable the definition of a unique parameter set for the description of the electronic structure of α ′ -NaV 2 O 5 .…”

Section: Introductionmentioning

confidence: 99%

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One-dimensional dynamics of thedelectrons inα′−NaV2O5
Atzkern
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We have studied the electronic properties of the ladder compound α ′ -NaV 2 O 5 adopting a joint experimental and theoretical approach. The momentumdependent loss function was measured using electron energy-loss spectroscopy in transmission. The optical conductivity derived from the loss function by a Kramers-Kronig analysis agrees well with our results from LSDA+U bandstructure calculations upon application of an antiferromagnetic alignment of the V 3d xy spins along the legs and an on-site Coulomb interaction U of between 2 and 3 eV. The decomposition of the calculated optical conductivity into contributions from transitions between selected energy regions of the DOS reveals the origin of the observed anisotropy of the optical conductivity. In addition, we have investigated the plasmon excitations related to transitions between the vanadium states within an effective 16 site vanadium cluster model. Good agreement between the theoretical and experimental loss function was obtained using the hopping parameters derived from the tight binding fit to the band-structure and moderate Coulomb interactions between 1 the electrons within the ab plane.

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Section: Optical Conductivitysupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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One-dimensional dynamics of thedelectrons inα′−NaV2O5
Atzkern
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,
Knupfer
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et al. 2001
Phys. Rev. B
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“…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].…”

mentioning

confidence: 99%

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

et al. 2001
Phys. Rev. B
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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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“…22 However, for NaV 2 O 5 one finds both experimentally 22,26,27 and theoretically 29 that the spectra depend only weakly on temperature. Therefore, we may restrict ourselves to zero temperature.…”

mentioning

confidence: 98%

Charge excitations inNaV2O5

et al. 2001

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We calculate the electron-energy loss spectrum and the optical conductivity for NaV2O5 using the standard Lanczos algorithm. The vanadium ions in NaV2O5 form a system of coupled ladders which can be described by a quarter-filled extended Hubbard model. Since this system has a large unit cell, one has to be very careful to avoid finite-size effects in the calculations. We show this by performing exact diagonalization of different clusters with up to 16 sites. The calculated loss function for the extended Hubbard model shows good agreement with experimental spectra. Furthermore, a qualitative description of the optical conductivity is obtained with the same Hamiltonian, and the same set of model parameters. The comparison with the experiment shows that interladder hopping is of minor importance for a realistic description of charge excitations in NaV2O5. We find that the character of the excitations depends strongly on the direction of momentum transfer.

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Polarized optical reflectance and electronic band structure ofα′−NaV2O

Cited by 27 publications

References 44 publications

One-dimensional dynamics of thedelectrons inα′−NaV2O5
Atzkern
¹
,
Knupfer
²
,
Golden
³

et al. 2001
Phys. Rev. B
17
6
27
0
View full text Add to dashboard Cite

One-dimensional dynamics of thedelectrons inα′−NaV2O5
Atzkern
¹
,
Knupfer
²
,
Golden
³

et al. 2001
Phys. Rev. B
17
6
27
0
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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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Charge excitations inNaV2O5

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Polarized optical reflectance and electronic band structure ofα′−NaV2O

Cited by 27 publications

References 44 publications

One-dimensional dynamics of thedelectrons inα′−NaV2O5Atzkern1, Knupfer2, Golden3 et al. 2001Phys. Rev. B176270View full textAdd to dashboardCite

One-dimensional dynamics of thedelectrons inα′−NaV2O5Atzkern1, Knupfer2, Golden3 et al. 2001Phys. Rev. B176270View full textAdd to dashboardCite

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

Charge excitations inNaV2O5

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One-dimensional dynamics of thedelectrons inα′−NaV2O5
Atzkern
¹
,
Knupfer
²
,
Golden
³

et al. 2001
Phys. Rev. B
17
6
27
0
View full text Add to dashboard Cite

One-dimensional dynamics of thedelectrons inα′−NaV2O5
Atzkern
¹
,
Knupfer
²
,
Golden
³

et al. 2001
Phys. Rev. B
17
6
27
0
View full text Add to dashboard Cite

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