Short range order in Ge–As–Se glasses

摘要: Abstract Short range order of glassy Ge 20 Ga 10 Se 70 and 5 75 was investigated by neutron diffraction extended X-ray absorption fine structure spectroscopy (EXAFS) at Ge, K-edges. For each composition large scale structural models were obtained fitting simultaneously the four experimental datasets in framework reverse Monte Carlo simulation technique. It found that both are predominantly fourfold coordinated. The quality fits strongly improved introducing Ge–Ga bonding. Models giving best agreement with data show has a complex effect on Ge–Se host matrix: i) it enters covalent network forming Ga–Ge bonds ii) decreasing number atoms around contributes to formation Se–Se bonds, which may explain higher solubility lanthanide ions iii) average coordination increases due Ga–Se ‘extra’ bonds. be responsible for increase T g upon adding glasses.