Structural Properties of Ge-S Amorphous Networks in Relationship with Rigidity Transitions: an Ab Initio Molecular Dynamics Study

We investigate the amorphous GexS100-x (with 10 <= x <= 40) system from ab initio simulations. Results show a very good agreement with experimental findings from diffraction and the topology of the obtained structural models is further analyzed and compared with the selenide analog. Differences emerge, however, from a detailed molecular dynamics analysis showing that the ring statistics and the homopolar defects do not evolve similarly. The findings are also connected to rigidity theory, which provides a topological approach to decoding the physics of network glasses, and the effects of composition and temperature are analyzed.