Research Papers in Physics and Astronomy


Date of this Version

December 1984


Published Phys. Rev. B. 30, 7122 (1984). Permission to use.


We present the results of Raman scattering measurements on the mixed-crystal systems TiSe2-xSx, TiSe2-xTex, ZrxTi1-x Se2. At room temperature with the pure compounds all have crystal structures represented by the D3d(P3̃m1) space group with three atoms per unit cell. There are two Raman-active k=0 phonons, one of A1gˉ symmetry and one of Eg symmetry. In the TiSe2-xTex system, the A1gˉ and E phonon frequencies shift smoothly with concentration, and the shifts are well described by a simple virtual-crystal model. The other two systems exhibit a two-mode behavior for which the virtual-crystal model does not correctly predict the observed frequency shifts. A random element isodisplacement model, based on Jaswal’s model for the pure-crystal lattice dynamics of TiSe2 is developed. This model correctly predicts several features of the observed Raman spectra with no adjustable parameters.

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