The localized vibrational modes of the 3d transition-metal ions (TMI’s) substituting for the cations in CdTe, ZnTe, and CdSe appear in infrared absorption with as many lines as there are isotopes of the impurity and with intensities proportional to their natural abundances. The triply degenerate local mode in a zinc-blende host splits into a singlet and a doublet in a wurtzite host, the former appearing only when the electric vector ( E) of the incident radiation is parallel to the optic axis (c^) and the latter when E⊥c^. Replacement of Cd by a TMI in CdSe results in high-frequency local vibrational as well as gap modes lying in the gap between the acoustic- and optic-phonon branches, the latter exhibiting an optical anisotropy similar to that of the former. Both the local and the gap modes exhibit a unique nonmonotonic trend across the 3d transition-metal series, with a minimum at Mn. © 1996 The American Physical Society.

• Received 9 November 1995

DOI:https://doi.org/10.1103/PhysRevB.53.12884