Bond lengths in Ge_1-xSi_x crystalline alloys grown by the Czochralski method

We measured the effect of alloy composition on the atomic bonding in bulk Ge_1-xSi_x alloys grown by the Czochralski method across the whole composition range 0<x<1. Extended x-ray-absorption fine-structure measurements performed at the Ge K edge at 20 K found that the Ge-Ge and Ge-Si bond lengths maintain distinctly different lengths and vary linearly with alloy composition. The topological rigidity parameter, estimated from the measured bond lengths, is around 0.6, which indicates that the bond lengths and bond angles are distorted with alloy composition.