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Title: Infrared study of α–SiO{sub 2} single crystal under high pressure

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 A{sub 2} 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 A{sub 2} 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 SiO{sub 4} 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.
Authors:
; ;  [1]
  1. MALTA Consolider Team, ICMUV, Universidad de Valencia, c/Dr. Moliner 50, 46100 Burjassot, Valencia (Spain)
Publication Date:
OSTI Identifier:
22494999
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 119; Journal Issue: 5; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BIREFRINGENCE; MONOCRYSTALS; PERMITTIVITY; PRESSURE RANGE MEGA PA 10-100; QUARTZ; SILICON OXIDES; SPECTRA