Ionic conduction pathways in noble metal chalcohalide glasses
High-energy X-ray diffraction, neutron diffraction and extended X-ray absorption fine structure experiments have been carried out for (MI)x(As2Se3)1−x glasses (M: Ag or Cu). The addition of a large amount of MI does not significantly affect short-range orderings of the host network matrix. The interatomic distance of M–I pairs is very similar to the case of crystalline MI. However, the coordination number of M–I pairs in the present glasses seems to be somewhat smaller than that in the crystalline MI, suggesting a heavy distortion of tetrahedral coordinates of MI units or structural disorder of the I–I sub-cages in the glass state. It would be predictable that the structure model for MI–As2Se3 glasses is proposed to be a pseudobinary mixture of the As(Se1/2)3 network matrix and MI-related conduction pathways.