Very sharp diffraction peak in nonglass-forming liquid with the formation of distorted tetraclusters

Understanding the liquid structure provides information that is crucial to uncovering the nature of the glass-liquid transition. We apply an aerodynamic levitation technique and high-energy X-rays to liquid ( l )-Er 2 O 3 to discover its structure. The sample densities are measured by electrostatic levitation at the International Space Station. Liquid Er 2 O 3 displays a very sharp diffraction peak (principal peak). Applying a combined reverse Monte Carlo – molecular dynamics approach, the simulations produce an Er–O coordination number of 6.1, which is comparable to that of another nonglass-forming liquid, l -ZrO 2 . The atomic structure of l -Er 2 O 3 comprises distorted OEr 4 tetraclusters in nearly linear arrangements, as manifested by a prominent peak observed at ~180° in the Er–O–Er bond angle distribution. This structural feature gives rise to long periodicity corresponding to the sharp principal peak in the X-ray diffraction data. A persistent homology analysis suggests that l -Er 2 O 3 is homologically similar to the crystalline phase. Moreover, electronic structure calculations show that l -Er 2 O 3 has a modest band gap of 0.6 eV that is significantly reduced from the crystalline phase due to the tetracluster distortions. The estimated viscosity is very low above the melting point for l -ZrO 2 , and the material can be described as an extremely fragile liquid. Liquid structure at extremely high temperature: levitation and quantum beam provide insights Experiments on the International Space Station (ISS) and SPring-8 have revealed properties and structure of liquid at the atomic level. X-ray diffraction provides detailed knowledge of the atomic structure of crystalline materials, but the technique is not so useful for liquids. Experiments on liquids are difficult because of the high temperatures often needed to create the liquid. To circumvent the problem, Chihiro Koyama from the Japan Aerospace Exploration Agency, Shinji Kohara from the National Institute for Materials Science, and co-workers performed density and high-energy X-ray diffraction measurements on levitating liquid erbium oxides in an electrostatic levitation furnace on the ISS and an aerodynamic levitation furnace at SPring-8, respectively. By combining the experimental data with computer simulations, the team were able to model the liquid’s structure and properties at both the atomic and electronic levels. The structure of a high-temperature non-glass forming liquid Er 2 O 3 was in