RAMAN SCATTERING AND SUPERCONDUCTIVITY OF AxC60

1992 ◽  
Vol 06 (23n24) ◽  
pp. 4013-4018 ◽  
Author(s):  
M.G. Mitch ◽  
S.J. Chase ◽  
J.S. Lannin
Keyword(s):  
Raman Scattering ◽  
Line Width ◽  
Ultrathin Films ◽  
Low Frequency ◽  
Phonon Coupling ◽  
Line Broadening ◽  
Vibrational Coupling ◽  
Electron Phonon Coupling ◽  
Scattering Measurements

Raman scattering measurements of line width variations in A x C 60 ultrathin films provide detailed information on vibrational coupling of H g or A g modes relevant to superconductivity. In situ, UHV studies of 400A thick Rb 3 C 60 and K 3 C 60 films indicate somewhat similar behavior, suggesting the predominance of low frequency H g (2) radial modes for electron-phonon coupling. Measurements of nonsuperconducting Na x C 60 in ultrathin films, in contrast, yield reduced line broadening effects for H g (8) and H g (2) modes relative to Rb and K materials.

Anomalous low-temperature Raman scattering in a–Si1−xHx

1995 ◽  
Vol 10 (6) ◽  
pp. 1362-1370 ◽  
Author(s):  
D.M. Bhusari ◽  
Alka Kumbhar ◽  
S.T. Kshirsagar
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Raman Scattering ◽  
Cross Section ◽  
Hydrogenated Amorphous Silicon ◽  
Phonon Coupling ◽  
Scattered Intensity ◽  
Electron Phonon Coupling ◽  
Scattering Measurements ◽  
Hydrogenated Amorphous

We have reported here on low-temperature Raman scattering measurements on thin films of hydrogenated amorphous silicon (α-Si:H) alloys having different H contents. The Stoke's intensity, 77KITO, scattered at 77 K by the TO-phonon is found to be several times greater than its corresponding magnitude (300KITO) at 300 K. The ratio (77KITO/300KITO) is observed to vary exponentially with an increase in H concentration of the film. After eliminating various possible contributions to the scattering cross section, and therefore to the scattered intensity, this anomalous light scattering at 77 K is attributed to the possibility of polarizability modulation, which is believed to be caused due to a possible reduction in light-induced migration of H in α-Si:H and to the charge-carrier-induced enhancement of electron phonon coupling at 77 K.

Raman Scattering and Superconductivity of Alkali-Fullerene Materials

1992 ◽  
Vol 270 ◽  
Author(s):  
J. S. Lannin ◽  
M. G. Mitch ◽  
W. Bacsa ◽  
S. J. Chase
Keyword(s):  
Thin Films ◽  
Raman Scattering ◽  
Raman Spectra ◽  
Solid Solutions ◽  
Thick Films ◽  
Ultrathin Film ◽  
Phonon Coupling ◽  
Electron Phonon Coupling ◽  
Scattering Measurements ◽  
Different Thickness

ABSTRACTRaman scattering measurements in alkali—fullerene alloys in ultrathin and thin films provide evidence for variations in electron—phonon coupling. For x — 3similar behavior of Rb3 C60 films of different thickness support substantial electron—phonon induced damping of specific Hg(i) modes derived from intramolecular modes of C60. In 400A thick films a reduction of induced scattering from Raman inactive C60 modes substantiates the importance ofHg(2), but not Hg(3) modes for phonon—mediated superconductivity. In contrast to RbxC60 and KxC60 ultrathin film solid solutions, similar Raman spectra for NaxC60 indicate substantially reduced coupling consistent with the absence of superconductivity in this system.

scholarly journals Resonance and antiresonance in Raman scattering in GaSe and InSe crystals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Osiekowicz ◽  
D. Staszczuk ◽  
K. Olkowska-Pucko ◽  
Ł. Kipczak ◽  
M. Grzeszczyk ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Temperature Effect ◽  
Band Gap ◽  
Raman Spectra ◽  
Quantum Interference ◽  
Optical Band Gap ◽  
Phonon Coupling ◽  
Phonon Modes ◽  
Electron Phonon Coupling ◽  
Resonant Raman

AbstractThe temperature effect on the Raman scattering efficiency is investigated in $$\varepsilon$$ ε -GaSe and $$\gamma$$ γ -InSe crystals. We found that varying the temperature over a broad range from 5 to 350 K permits to achieve both the resonant conditions and the antiresonance behaviour in Raman scattering of the studied materials. The resonant conditions of Raman scattering are observed at about 270 K under the 1.96 eV excitation for GaSe due to the energy proximity of the optical band gap. In the case of InSe, the resonant Raman spectra are apparent at about 50 and 270 K under correspondingly the 2.41 eV and 2.54 eV excitations as a result of the energy proximity of the so-called B transition. Interestingly, the observed resonances for both materials are followed by an antiresonance behaviour noticeable at higher temperatures than the detected resonances. The significant variations of phonon-modes intensities can be explained in terms of electron-phonon coupling and quantum interference of contributions from different points of the Brillouin zone.

Raman scattering and tunable electron–phonon coupling in single layer graphene

2007 ◽  
Vol 143 (1-2) ◽  
pp. 39-43 ◽  
Author(s):  
Jun Yan ◽  
Yuanbo Zhang ◽  
Sarah Goler ◽  
Philip Kim ◽  
Aron Pinczuk
Keyword(s):  
Raman Scattering ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Phonon Coupling ◽  
Layer Graphene ◽  
Electron Phonon Coupling

Raman scattering from impurities in semiconductors. II. Special cases

1978 ◽  
Vol 56 (5) ◽  
pp. 560-564
Author(s):  
Robert Barrie ◽  
H. -C. Chow
Keyword(s):  
Raman Scattering ◽  
General Result ◽  
Phonon Scattering ◽  
Phonon Coupling ◽  
Strong Electron ◽  
Impurities In Semiconductors ◽  
Electron Phonon Coupling ◽  
Special Cases ◽  
Weak Electron

Special cases of the general result for Raman scattering from an impurity in a semiconductor are discussed. For weak electron–phonon coupling the zero-phonon and one-phonon scattering intensities are derived. For strong electron–phonon coupling a comparison is made between two different approximations that have been previously used.

Raman scattering and electron-phonon coupling inRbxC60

1992 ◽  
Vol 68 (6) ◽  
pp. 883-886 ◽  
Author(s):  
Michael G. Mitch ◽  
Sabrina J. Chase ◽  
Jeffrey S. Lannin
Keyword(s):  
Raman Scattering ◽  
Phonon Coupling ◽  
Electron Phonon Coupling
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