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Title: Raman spectroscopy of isotopically pure ({sup 12}C, {sup 13}C) and isotopically mixed ({sup 12.5}C) diamond single crystals at ultrahigh pressures

Journal Article · · Journal of Experimental and Theoretical Physics
; ;  [1];  [2];  [1]
  1. Russian Academy of Sciences, Troitsk, Institute for High-Pressure Physics (Russian Federation)
  2. National Institute for Materials Science (Japan)

The Raman scattering by isotopically pure {sup 12}C and {sup 13}C diamond single crystals and by isotopically mixed {sup 12.5}C diamond single crystals is studied at a high accuracy. The studies are performed over a wide pressure range up to 73 GPa using helium as a hydrostatic pressure-transferring medium. It is found that the quantum effects, which determine the difference between the ratio of the Raman scattering frequencies in the {sup 12}C and {sup 13}C diamonds and the classical ratio (1.0408), increase to 30 GPa and then decrease. Thus, inversion in the sign of the quantum contribution to the physical properties of diamond during compression is detected. Our data suggest that the maximum possible difference between the bulk moduli of the {sup 12}C and {sup 13}C diamonds is 0.15%. The investigation of the isotopically mixed {sup 12.5}C diamond shows that the effective mass, which determines the Raman frequency, decreases during compression from 12.38 au at normal pressure to 12.33 au at 73 GPa.

OSTI ID:
22617186
Journal Information:
Journal of Experimental and Theoretical Physics, Vol. 123, Issue 3; Other Information: Copyright (c) 2016 Pleiades Publishing, Inc.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7761
Country of Publication:
United States
Language:
English