Network connectivity and extended Se chains in the atomic structure of glassy GeSe4

► Glassy GeSe4 structure was investigated using molecular dynamics simulations. ► We report the existence of long Se chains interconnecting GeSe4 tetrahedra. ► The homogeneous model consisting of GeSe4 tetrahedra can be discarded. ► A pure phase separation model (GeSe2 and Se) is also highly unlikely. ► Different functionals (PW and PBE) lead to consistent structural results.