Short range order Ge-S and Ge-(Ga,Sb)-S glasses

Ge-(Ga,Sb)-S glasses are widely used in infrared optics. Despite the practical importance their short range order is still not understood completely. The main problem is that both the size and scattering properties of Ge and Ga atoms are similar making it difficult to catch differences in their local environments experimentally. In addition, long Sb-S bonds were also found in Ge-Sb-S glasses, suggesting that SbS3 units may not be prevailing in this system. We aim to obtain structural models by combining neutron diffraction and x-ray diffraction structure factors (both up to at least 25 A-1) with X-ray absorption fine structure data. We believe that high real space resolution of GEM data will facilitate to detect potential differences in local order around Ge and Ga and it will also help to understand the origin of long Sb-S bonds.

锗-(镓,锑)-硫系玻璃（Ge-(Ga,Sb)-S glasses）已被广泛应用于红外光学领域。尽管该体系具有重要的实用价值，但其短程有序结构仍未被完全阐明。核心难点在于锗与镓原子的尺寸及散射特性极为相近，导致实验上难以区分二者的局域环境差异。此外，研究人员在锗-锑-硫玻璃中还观测到了超长锑-硫键，这表明SbS₃结构单元在该体系中并非主导结构。本研究旨在通过结合中子衍射（neutron diffraction）与X射线衍射（x-ray diffraction）结构因子（二者的最大散射矢量均至少达到25 Å⁻¹）以及X射线吸收精细结构（X-ray absorption fine structure）数据，构建该体系的精准结构模型。我们认为，GEM数据具备优异的实空间分辨率，将有助于识别锗与镓原子周围局域有序结构的潜在差异，同时也能助力阐明超长锑-硫键的成因。