Lattice vibrational properties of superhard rhenium diboride (ReB2) were examined up to 8 GPa in a diamond anvil cell using Raman spectroscopy techniques. Linear pressure coefficients and mode Grüneisen parameters are obtained. Good agreement is found between the experimental and theoretical calculated Grüneisen parameters. Examination of the calculated mode Grüneisen parameters reveals that both B-B and Re-B covalent bonds play a dominant role in supporting the applied load under pressure. A comparison of vibrations parallel and perpendicular to the c-axis indicates that bonds along the c-axis tend to take greater loads. Our results agree with observations of elastic lattice anisotropy obtained from both in situ X-ray diffraction measurements and ultrasonic resonance spectra.
Raman scattering from superhard rhenium diboride under high pressure
Present address: Laboratory of Seismology and Physics of Earth's Interior, School of Earth and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.
Miao Xie, Björn Winkler, Zhu Mao, Richard B. Kaner, Abby Kavner, Sarah H. Tolbert; Raman scattering from superhard rhenium diboride under high pressure. Appl. Phys. Lett. 6 January 2014; 104 (1): 011904. https://doi.org/10.1063/1.4858410
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