Resonant Raman Scattering near E1 + Δ1 in CdxHg1−xSe

Raman scattering by phonons is measured in CdxHg1−xSe with x = 0 to 0.3 on (100), (110) and (111) surfaces near the E1 + Δ1 energy gap at room temperature. From these measurements, the composition dependence of the HgSe‐like TO and LO mode frequencies is obtained. The plasmon‐LO phonon coupled modes and a cluster mode are also observed. Effective high‐frequency dielectric constants calculated by the extended Lyddane‐Sachs‐Teller relation show a discontinuity near the semimetal‐semiconductor transition point. This discontinuity is attributed to the contribution of interband terms to the dielectric function. The results obtained from the Raman measurements are compared with those from far‐infrared measurements.