Detailed investigations on short- and intermediate-range structures of Ge-Se glasses near the stiffness transition composition

Hosokawa, Shinya*; Kawakita, Yukinobu  ; Pusztai, L.*; Ikeda, Kazutaka*; Otomo, Toshiya*

In order to improve the reliability of short- and intermediate-range atomic structures of GeSe glasses, high quality neutron diffraction data, in both the real and reciprocal spaces, were added to the existing anomalous X-ray scattering and X-ray diffraction datasets [Hosokawa et al., Phys. Rev. B 84, 014201 (2011)] for reverse Monte Carlo modeling. This addition proved to be highly effective for obtaining well-refined structural data and for revealing a close relationship between the compositional stiffness transition occurring at about = 0.20-0.26 and the partial structures. Although the and functions gradually change with varying , important indications on the stiffness transition are confirmed on the basis of the intermediate-range element-selective atomic structures () more clearly than it was possible by previous results. An abrupt decrease in terms of the the prepeak intensity of , a rapid disappearance of the Ge-Ge homopolar bonds, anomalies in the ratio of edge- and corner-sharing Ge(Se) tetrahedra, and characteristic changes in the tetrahedral connections with decreasing X across the so-called intermediate phase have all been observed.