Bond-stretching force constants and vibrational frequencies in ternary zinc-blende alloys: A systematic comparison of (In,Ga)P, (In,Ga)As and Zn(Se,Te)

We present element-specific effective bond-stretching force constants and Einstein frequencies of (In,Ga)P ternary alloys determined by temperature-dependent extended x-ray absorption fine structure spectroscopy. The bond-stretching force constants of both bond species show a nearly linear composition dependence between the values of GaP and InP. In contrast, the corresponding Einstein frequencies are different for the two bond species over the whole compositional range. Furthermore, we demonstrate that the composition dependence of bond-stretching force constants and Einstein frequencies for (In,Ga)P, (In,Ga)As, and Zn(Se,Te) is mostly caused by the associated bond length changes. Remaining deviations may be explained by coupling effects between different bond species within the alloy.