Short range order of As 40-x Cu x Te 60 glasses

Short range order of As40-xCuxTe60 (x=0, 10, 20, 25, 30) glasses was studied by neutron- and X-ray diffraction, combined with extended X-ray absorption fine structure (EXAFS) measurements at the K-edges of all components. Large-scale structural models were generated by fitting the experimental datasets simultaneously in the framework of the reverse Monte Carlo simulation technique. These simulations revealed that As and Te atoms bind to about 3 and 2 As/Te neighbors, respectively, both of which possess Cu neighbors. The CuTe bond length is 2.57±0.02Å while the CuAs distance is as high as 2.86±0.04Å. The results further showed that besides As and Te, Cu atoms also bind to Cu. The total coordination number of Cu is significantly higher than 4 for the compositions x=25 and 30.