Research Papers in Physics and Astronomy
Date of this Version
The first-order Raman spectra of the mixed-crystal layered compound HfxTi1-xSe2 have been studied over the whole range of concentrations 0≤x≤1. Both pure compounds, TiSe2 and HfSe2, have the CdI2 structure and so have two Raman-active phonons of A1g phonon is at about 205 cm -1. As x is decreased from 1.0, a new Raman peak, of A1g symmetry, appears near 180 cm -1. As x is decreased further, this peak shifts smoothly upwards in frequency, until it finally merges (by x=0.05) with the pure TiSe2 A1g phonon. A modified random-element isodisplacement model involving only short-range forces is developed to describe the observed concentration dependences of the frequencies of these phonons. The calculated concentration dependences are in good quantitative agreement with the experimental results.
Published Phys. Rev. B 40, 1152 (1989). Permission to use.