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LiBC by polarized Raman spectroscopy: Evidence for lower crystal symmetry ?

J. Hlinka·I. Gregora·J. Pokorny·A. V. Pronin·A. Loidl
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Abstract

The paper presents polarized Raman scattering study on a few-micron-size crystallite of LiBC with natural faces. The experiment on as grown sample has revealed a four lattice modes with frequencies at 1276 cm^-1, 830 cm^-1, 546 cm^-1 and 170 cm^-1, respectively. The number of observed Raman lines and their selection rules are incompatible with the assumed D6h symmetry. The modes at 1276 cm^-1 and 170 cm^-1 correspond to the expected Raman active modes. In contrast with the superconducting compound MgB2, the B-C bond stretching mode (at 1276 cm^-1) has rather small damping. The two "forbidden" modes (at 830 cm^-1 and 546 cm^-1) disappeared after subsequent thermal treatment.

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J. Hlinka, I. Gregora, J. Pokorny, A. V. Pronin, A. Loidl. 2002-09-10. LiBC by polarized Raman spectroscopy: Evidence for lower crystal symmetry ?. https://doi.org/10.1103/physrevb.67.020504

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