Germanene-like defects in Reverse Monte Carlo model of amorphous germanium revealed through new visualization method

High Resolution x-ray diffraction experiments of amorphous germanium (a-Ge) revealed structural differences that cannot be reconciled with accepted theoretical models. An intuitive computational technique has been developed to construct 3D statistical density maps to directly resolve local atomic structure of a-Ge. A reverse monte carlo routine is used to compare the continuous random network model to the experimental model of a-Ge. Undercoordination in the refined model is shown to exist bimodally, as a $4$-coordinated tetrahedron and a buckled $3$-coordinated structure similar to germanene. These structures account for $95.7\%$ of the total atoms in an approximate $5$:$2$ ratio respectively.