Raman Scattering Investigation of Superconductivity in Si46 Clathrates

1996 ◽  
Vol 452 ◽  
Author(s):  
S. L. Fang ◽  
L. Grigorian ◽  
A. M. Rao ◽  
P. C. Eklund ◽  
G. Dresselhaus ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Room Temperature ◽  
Line Broadening ◽  
Phonon Interaction ◽  
Metallic Behavior ◽  
Type Ii Superconductors ◽  
First Order ◽  
Electron Phonon Interaction ◽  
Scattering Spectra ◽  
Raman Scattering Spectra

AbstractRoom temperature Raman scattering spectra are reported for the type II superconductors MxBaySi46 (M-Na, K) which were recently shown to exhibit Tc's ∼ 3.5 K. The spectra are compared to those of other Si46-clathrates which exhibit normal metallic behavior down to 2K. Thirteen of the twenty first-order Raman frequencies predicted by group theory have been detected, and the frequencies are found to be sensitive to the particular dopants. The Raman linewidths observed for the MxBaySi46 system are comparable to those observed for Na8Si46 and K7Si46. The data, taken collectively, suggest that the line broadening in the metallic Si-clathrates is due to important contributions from both the electron-phonon interaction as well as to a random filling of the Si cages.

STRUCTURE AND TRANSPORT PROPERTIES OF Pr1-xSr1+xCoO4

2008 ◽  
Vol 22 (32) ◽  
pp. 3195-3205 ◽  
Author(s):  
M. LI ◽  
S. L. HUANG ◽  
Z. M. LV ◽  
J. L. ZHANG ◽  
H. Y. WU ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Low Frequency ◽  
X Ray Diffraction ◽  
Phonon Interaction ◽  
Band Shift ◽  
X Ray ◽  
Electron Phonon Interaction ◽  
Scattering Spectra ◽  
Raman Scattering Spectra ◽  
Dramatic Variation

Powder X-ray diffraction, Raman scattering and infrared spectra at different doping (x = 0 ~ 0.5) on polycrystalline Pr 1-x Sr 1+x CoO 4 were performed. With increasing x, the shift of Raman scattering spectra is due to the enhancement of electron–phonon interaction along the c-axis. The contrary variation of infrared in wavenumber comes from the weakening electron–phonon interactions in the ab plane. There is a dramatic variation in resistivity as x increases, which is also caused by increasing carrier concentration and is related to the band shift. For Pr 1-x Sr 1+x CoO 4, both A1g bands shift to low frequency and reach a minimum when x = 0.3 and the resistivity of Pr 0.7 Sr 1.3 CoO 4 is the smallest at room temperature.

Defects Characterization of GaN Substrate with Hot Implant Process

2020 ◽  
Vol 1004 ◽  
pp. 497-504
Author(s):  
Junko Maekawa ◽  
Hitoshi Kawanowa ◽  
Masahiko Aoki ◽  
Katsumi Takahiro ◽  
Toshiyuki Isshiki
Keyword(s):  
Raman Scattering ◽  
Defect Structure ◽  
Room Temperature ◽  
Spectroscopic Analysis ◽  
Depth Scale ◽  
Scattering Spectra ◽  
Raman Scattering Spectra ◽  
Better Than

The defect structure of Mg implanted GaN substrate was evaluated by TEM observations, AFM surface observations and Raman scattering spectroscopic analysis. Mg ions were implanted at room temperature (RT) and 500 °C. TEM results showed that the defect distribution along depth scale is different between RT and 500 °C condition. The several peaks originated from ion implantation were found from Raman scattering spectra and the characteristics of the defects by implantation were discussed. The crystal quality of the sample implanted at 500 °C was found to be better than that of RT by comparing the FWHM of the E2 peak.

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