Structural observation of Li₂S-GeS₂ superionic glasses

Time-of-flight neutron diffraction measurements have been performed to investigate the structure of Li₂S-GeS₂ superionic glasses synthesized by mechanical alloying. The total correlation functions have the positive and the negative peaks, which correspond to Ge-S and Li-S nearest-neighbour correlations, respectively. The coordination number of S atoms around a Ge atom indicates that Ge atom is tetrahedrally coordinated by S atoms and GeS₄ tetrahedra consist of not only bridging S but also non-bridging S. The coordination number of S atoms around a Li atom indicates that mobile Li ions are coordinated by three non-bridging S.