Physical nature of quasi-stable structures existing in antimony melt

TL;DR

This study reveals that liquid antimony near its melting point contains quasi-stable, low-order atomic triplet structures with specific lengths and angles, which form chains and clusters, explaining unique structural features observed experimentally.

Contribution

It provides the first detailed characterization of quasi-stable atomic triplet structures in antimony melt using quantum calculations and diffraction data.

Findings

Identification of triplet units with specific lengths and angles.

Triplet chains and clusters up to 15 Å in length.

Correlation of triplet structures with diffraction-based short-range order.

Abstract

Equilibrium antimony melt near the melting temperature is characterised by structural features that are not present in simple single-component liquids. The cause of these features may be long-lived structural formations that are not yet fully understood. The present work provides the detailed characterization of the structures formed in liquid antimony near the melting temperature based on the results of quantum chemical calculations and the available neutron and X-ray diffraction data. The quasi-stable structures in antimony melt are detected with lifetimes exceeding the structural relaxation time of this melt. These structures are characterised by a low degree of order and spatial localisation. It is shown for the first time that the elementary units of these quasi-stable structures are triplets of atoms with characteristic lengths of $3.07$\,\AA~and $4.7$\,\AA~and characteristic angles of $45$ and $90$ degrees. It was found that these triplets can form chains and percolating clusters up to $\sim15$\,\AA~in length. The characteristic lengths of these triplets are fully consistent with the correlation lengths associated with short-range order in the antimony melt as determined by diffraction experiments.