Resonance Raman scattering by LO phonons in CdxHg1−xTe at the E0+Δ0 gap

Abstract

We have studied the resonance of the first- and second-order Raman scattering by LO phonons in ${\mathrm{Cd}}_{\mathrm{x}}$ ${\mathrm{Hg}}_{1\mathrm{-}\mathrm{x}}$Te for x≊1 near the $E_0$+${\Delta }_0$ gap. We show that the effect of alloying is a shift and a broadening of the resonances which can be compared with calculations of the compositional dependence of the gaps. The mechanisms contributing to one-LO-phonon and two-LO-phonon scattering are discussed and experimentally investigated. We give absolute values for the Raman efficiencies and compare them with theory.