6533b7d9fe1ef96bd126c07b
RESEARCH PRODUCT
Infrared study of α–SiO2 single crystal under high pressure
Alfredo SeguraJulio Pellicer-porresDavid Santamaría-pérezsubject
PermittivityBirefringenceChemistryInfraredAnalytical chemistryGeneral Physics and AstronomyInfrared spectroscopy02 engineering and technologyDielectric021001 nanoscience & nanotechnologyPolarization (waves)01 natural sciencesMolecular physicsSpectral line0103 physical sciences010306 general physics0210 nano-technologySingle crystaldescription
We have measured high pressure α-quartz reflectance spectra in the mid infrared. We used single crystals, taking full profit of polarization. The quality of the spectra allows fitting the reflectance spectra. We have characterized the pressure evolution of E and A2 modes with increased precision, even in the spectral regions where they overlap. In addition, we have determined the TO-LO splitting of each mode. Some of the A2 modes show dramatic pressure variations of the LO-TO splitting, which cannot be explained only by changes in length and ionicity of individual bonds, requiring a new mechanism. We suggest that rotation of the SiO4 tetrahedra plays a fundamental role. We have also determined the evolution of the electronic dielectric constant under high pressure. We find that its pressure increment is mainly a volume effect, although the small increase in birefringence points to secondary changes associated to the electronic resonances.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2016-02-07 | Journal of Applied Physics |