Short range order in anomalous liquid metals

• Published in: Journal of non-crystalline solids Vol. 358; no. 18-19; pp. 2687 - 2694
• Main Authors: Shor, Yulia, Yahel, Eyal, Makov, Guy
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 15.09.2012; Elsevier
• Subjects: Anomalous liquids; Condensed matter: structure, mechanical and thermal properties; Crystalline state (including molecular motions in solids); Exact sciences and technology; Physics; Pnictides; Quasi-crystalline model; Quasicrystals; Semi-periodic solids; Short range order; Structure of solids and liquids; crystallography; Theory of crystal structure, crystal symmetry; calculations and modeling; Pnictides; Quasi-crystalline model; Short range order; Anomalous liquids; Coordination number; Melting; Structure factors; Anomalous properties; Diffraction pattern; Liquid metals; Quasicrystals; Solid structure; Physical properties; Bond lengths; Sound velocity; Structural models; Asymmetry; Radial distribution function; Short-range order; Anomaly; Liquid structure
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2012.06.025

Liquid metals with anomalous physical properties such as increasing sound velocity with temperature or density anomalies, exhibit a complex structure in their one dimensional experimental diffraction patterns. Typically, their radial distribution functions are characterized by an asymmetric first peak and a subsidiary peak or shoulder on the right hand side of the first main peak. It has been hypothesized that the complex structure is associated with short range ordering the liquid. Specifically in the liquid pnictides, it has been proposed that such order may be associated with the underlying solid A7 structure. We present an analysis of the short range order in liquids using a modified quasi-crystalline model of liquid structure. This model is shown to fit the experimental radial distribution function very well and to reproduce the experimentally observed structure factor. Using this model we find that the short range order in the liquid pnictides is dominated by an A7-like structure with two types of bonds, in close agreement with the underlying solid phase. The existence of two bond lengths is necessary within this model to explain the asymmetry in the first peak as well as the change in coordination number along the pnictide series. The quasi-crystalline model is discussed and shown to correlate with the Lindemann melting criterion. ► Study the short range order in group V liquids in a modified quasi-crystalline model. ► Fit the experimental radial distribution function and reproduce the structure factor. ► Short range order is A7-like with two types of bonds like the solid phase. ► Model asymmetry in first peak and the change in coordination number in the series.