Linewidth behavior of the A1g Raman phonon in CdxHg1-xI2 solid solution

The behavior of the A1g phonon line in CdxHg1-xI2 (with 0<x<0.38) solid solution has been investigated by Raman spectroscopy between 20 and 300 K. At room temperature, the A1g linewidth unexpectedly decreases as the cadmium concentration is increased; at low temperature, the more conventional opposite trend is observed. By taking into account a variation of the final density of states in which the A1g phonon decays, a convincing explanation of the experimental results is given. In addition, useful information on the behavior of the boundary LO(X) and/or LA(X) phonons in the solid solution can be extracted.