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Kakihana, Masato; Osada, Minoru; Käll, Mikael; Börjesson, Lars; Mazaki, Hiromasa; Yaśuoka, Hiroshi; Yashima, Masatomo; Yoshimura, Masahiro

doi:10.1103/physrevb.53.11796

Cited by 100 publications

(73 citation statements)

References 60 publications

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“…Our calculated results for the infrared-active 2u A modes are in good agreement with new experiments obtained by ellipsometric measurements on single crystals [48]. The assignments of the c-axis 2u A -IR-phonons are discussed controversially in the literature [49,50] and also as far as the Raman-active 1g A modes are concerned different experimental groups have published rather different and contradictory assignments [51][52][53]. In particular the origin of the high-frequency vibrations around 460 and 630 cm -1 in the Raman spectra of Bi-2212 is controversial and there is a strong dispute concerning the question of which mode can be attributed to the oxygens O 2 located in the SrO plane and which one to the oxygens O 3 in the BiO plane.…”

Section: Infrared-and Raman-active C-axis Modes Of Bi-based Cuprate Ssupporting

confidence: 89%

Phonons, electronic charge response and electron–phonon interaction in the high‐temperature superconductors

Falter¹

2004

Physica Status Solidi (b)

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We investigate the complete phonon dispersion, the phonon induced electronic charge response and the corresponding self-consistent change of the crystal potential an electron feels as a direct measure of the electron-phonon interaction in the high-temperature superconductors within a microscopic model in the framework of linear response theory. Moreover, dielectric and infrared properties are calculated. The experimentally observed strong renormalization of the in-plane oxygen bond-stretching modes which appears upon doping in the high-temperature superconductors is discussed. It is shown that the characteristic softening, indicating a strong nonlocal electron-phonon interaction, is most likely a generic effect of the CuO plane and is driven by a nonlocal coupling of the displaced ions to the localized charge-fluctuations at the Cu and the O xy ions. At hand of the oxygen bond-stretching modes it is illustrated how lattice-, charge-and spin-degrees of freedom may act synergetically for anisotropic pairing in the hightemperature superconductors. The different behaviour of these modes during the insulator-metal transition via the underdoped phase is calculated and from a comparison of these generic modes in the different phases conclusions about the electronic state are drawn. For the non-cuprate potassium doped hightemperature superconductor Ba-Bi-O also a very strong and anisotropic renormalization of the oxygen bond-stretching modes is predicted. In another investigation c-axis polarized infrared-and Raman-active modes of the HTSC's are calculated in terms of charge fluctuations and anisotropic dipole-fluctuations. Mode assignments discussed controversially in the literature are proposed. Finally, interlayer phonons propagating along the c-axis and their accompanying charge response are investigated. Depending on the strength of the interlayer coupling calculations are performed ranging from the static, adiabatic response regime to the non-adiabatic regime where dynamical screening of the bare Coulomb interaction and phonon-plasmon coupling becomes relevant within a certain region around the direction of the c-axis. A comparison with the experimental situation is given. Both, the oxygen bond-stretching modes calculated in adiabatic approximation and the non-adiabatic coupled c-axis phonon-plasmon modes are found to be important for pairing via lattice-and charge-degrees of freedom. Favouring aspects to achieve hightemperature superconductivity are also discussed.

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Section: Infrared-and Raman-active C-axis Modes Of Bi-based Cuprate Ssupporting

confidence: 89%

Phonons, electronic charge response and electron–phonon interaction in the high‐temperature superconductors

Falter¹

2004

Physica Status Solidi (b)

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“…37 Our results do contain a B g component very close to this frequency, but we caution that it is accompanied by a very strong A g signal, and may only be a shadow of this mode arising due to a disorder-induced mixing of local symmetries. 41 In the general context of phase separation, it is clear that our samples have both a robust structural and magnetic order (from the neutron diffraction studies performed on the same crystals) and a clear superconducting component. We have been unable to find any evidence for the presence of secondary phases in X-ray and neutron-scattering studies, 14,42 and we show in Fig.…”

Section: Discussionmentioning

confidence: 99%

Effect of iron content and potassium substitution inA0.8Fe1.6Se2
Zhang
¹
,
Liu
²
,
He
³

et al. 2012
Phys. Rev. B
17
4
12
0
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We have performed Raman-scattering measurements on high-quality single crystals of the superconductors K0.8Fe1.6Se2 (Tc = 32 K), Tl0.5K0.3Fe1.6Se2 (Tc = 29 K), and Tl0.5Rb0.3Fe1.6Se2 (Tc = 31 K), as well as of the insulating compound KFe1.5Se2. To interpret our results, we have made first-principles calculations for the phonon modes in the ordered iron-vacancy structure of K0.8Fe1.6Se2. The modes we observe can be assigned very well from our symmetry analysis and calculations, allowing us to compare Raman-active phonons in the AFeSe compounds. We find a clear frequency difference in most phonon modes between the superconducting and non-superconducting potassium crystals, indicating the fundamental influence of iron content. By contrast, substitution of K by Tl or Rb in A0.8Fe1.6Se2 causes no substantial frequency shift for any modes above 60 cm −1 , demonstrating that the alkali-type metal has little effect on the microstructure of the FeSe layer. Several additional modes appear below 60 cm −1 in Tl-and Rb-substituted samples, which are vibrations of heavier Tl and Rb ions. Finally, our calculations reveal the presence of "chiral" phonon modes, whose origin lies in the chiral nature of the K0.8Fe1.6Se2 structure.

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“…It has been generally found that a larger number of phonon modes occur in the Raman spectra of the Bi-based compounds than would [9,45,47]. However, recently it was argued that the assignment should be reversed [48,49]. It was shown that these two bands exhibit different polarization dependencies for the incident and scattered vectors, indicating that the degree of mode mixing is small, and the 620 cm −1 band is strongly c -polarized like apex oxygen vibrations characteristic for most high-T c superconductors [48].…”

Section: Theoretical Calculations a Shell Model Approximation Andmentioning

confidence: 99%

“…However, recently it was argued that the assignment should be reversed [48,49]. It was shown that these two bands exhibit different polarization dependencies for the incident and scattered vectors, indicating that the degree of mode mixing is small, and the 620 cm −1 band is strongly c -polarized like apex oxygen vibrations characteristic for most high-T c superconductors [48]. Moreover, the 460 cm −1 band has been found to soften at a significantly faster rate than the 620 cm −1 band with 18 O oxygen isotope substitution, in agreement with the more liable oxygen atoms from the BiO layer [49].…”

Section: Theoretical Calculations a Shell Model Approximation Andmentioning

confidence: 99%

c-axis lattice dynamics in Bi-based cuprate superconductors

et al. 2004

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We present results of a systematic study of the c axis lattice dynamics in single layer Bi 2 Sr 2 CuO 6 (Bi2201), bilayer Bi 2 Sr 2 CaCu 2 O 8 (Bi2212) and trilayer Bi 2 Sr 2 Ca 2 Cu 3 O 10 (Bi2223) cuprate superconductors. Our study is based on both experimental data obtained by spectral ellipsometry on single crystals and theoretical calculations. The calculations are carried out within the framework of a classical shell model, which includes long-range Coulomb interactions and short-range interactions of the Buckingham form in a system of polarizable ions. Using the same set of the shell model parameters for Bi2201, Bi2212 and Bi2223, we calculate the frequencies of the Brillouin-zone center phonon modes of A 2u symmetry and suggest the phonon mode eigenvector patterns. We achieve good agreement between the calculated A 2u eigenfrequencies and the experimental values of the c axis TO phonon frequencies which allows us to make a reliable phonon mode assignment for all three Bi-based cuprate superconductors. We also present the results of our shell model calculations for the Γ-point A 1g symmetry modes in Bi2201, Bi2212 and Bi2223 and suggest an assignment that is based on the published experimental Raman spectra. The superconductivity-induced phonon anomalies recently observed in the c axis infrared and resonant Raman scattering spectra in trilayer Bi2223 are consistently explained with the suggested assignment.

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Raman-active phonons inBi2Sr2
Masato Kakihana
¹
,
Minoru Osada
²
,
Mikael Käll
³

et al.

Cited by 100 publications

References 60 publications

Phonons, electronic charge response and electron–phonon interaction in the high‐temperature superconductors

Phonons, electronic charge response and electron–phonon interaction in the high‐temperature superconductors

Effect of iron content and potassium substitution inA0.8Fe1.6Se2
Zhang
¹
,
Liu
²
,
He
³

et al. 2012
Phys. Rev. B
17
4
12
0
View full text Add to dashboard Cite

c-axis lattice dynamics in Bi-based cuprate superconductors

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Raman-active phonons inBi2Sr2Masato Kakihana1, Minoru Osada2, Mikael Käll3 et al.

Cited by 100 publications

References 60 publications

Phonons, electronic charge response and electron–phonon interaction in the high‐temperature superconductors

Phonons, electronic charge response and electron–phonon interaction in the high‐temperature superconductors

Effect of iron content and potassium substitution inA0.8Fe1.6Se2Zhang1, Liu2, He3 et al. 2012Phys. Rev. B174120View full textAdd to dashboardCite

c-axis lattice dynamics in Bi-based cuprate superconductors

Contact Info

Product

Resources

About

Raman-active phonons inBi2Sr2
Masato Kakihana
¹
,
Minoru Osada
²
,
Mikael Käll
³

et al.

Effect of iron content and potassium substitution inA0.8Fe1.6Se2
Zhang
¹
,
Liu
²
,
He
³

et al. 2012
Phys. Rev. B
17
4
12
0
View full text Add to dashboard Cite