NEUTRON-DIFFRACTION STUDY OF LIQUID GETE AND AS2TE3

The radial distribution analyses for GeTe and As2Te3 are made at temperatures above the melting point in the range of momentum transfer between 0.7 and 10.0 Å-1 by the neutron diffraction technique. Furthermore, the local order in amorphous GeTe is determined by analyzing the intensity data of the electron diffraction of its thin film. The result for the amorphous film indicates that the local distribution of atoms in amorphous GeTe is not characteristic of the structure of its crystalline state. The shape of the peaks of the intensity curve for liquid GeTe differs from that for the amorphous and crystalline states. However, the short bond length and the small coordination number determined from liquid RDF suggest that the covalent-like bonding between nearest-neighbor atoms remains unbroken when melting. The general form of the structure factor for liquid As2Te3 is similar to that for the amorphous material reported previously. The position of the first peak of RDF in the liquid state is observed to be shifted to a shorter distance than the average of nearest-neighbor atoms in crystalline As2Te3. The structure of GeTe differs considerably between the crystalline, amorphous and liquid states, whereas the local order in the liquid As2Te3 is similar to that in the amorphous state but not in the crystalline state. © 1979.