Vibrational dynamics of rutile-type GeO2 from micro-Raman spectroscopy experiments and first-principles calculations

The vibrational dynamics of germanium dioxide in the rutile structure has been investigated by using polarized micro-Raman scattering spectroscopy coupled with first-principles calculations. Raman spectra were carried out in backscattering geometry at room temperature from micro-crystalline samples...

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Bibliographic Details
Published in:Europhysics letters 2015-01, Vol.109 (2), p.26007
Main Authors: Sanson, A., Pokrovski, G. S., Giarola, M., Mariotto, G.
Format: Article
Language:English
Subjects:
63.70.+h
78.20.-e
78.30.Er
Density functional theory
Dynamic structural analysis
Excitation spectra
First principles
Germanium
Germanium oxides
Group theory
Line spectra
Micromanipulation
Raman spectra
Raman spectroscopy
Resonance scattering
Room temperature
Rutile
Vibrational spectra
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Summary:The vibrational dynamics of germanium dioxide in the rutile structure has been investigated by using polarized micro-Raman scattering spectroscopy coupled with first-principles calculations. Raman spectra were carried out in backscattering geometry at room temperature from micro-crystalline samples either unoriented or oriented by means of a micromanipulator, which enabled successful detection and identification of all the Raman active modes expected on the basis of the group theory. In particular, the Eg mode, incorrectly assigned or not detected in the literature, has been definitively observed by us and unambiguously identified at under excitation by certain laser lines, thus revealing an unusual resonance phenomenon. First-principles calculations within the framework of the density functional theory allow quantifying both wave number and intensity of the Raman vibrational spectra. The excellent agreement between calculated and experimental data corroborates the reliability of our findings.
ISSN:0295-5075
1286-4854
DOI:10.1209/0295-5075/109/26007