Atomic and electronic structures of an extremely fragile liquid

Area of Science:

• Materials Science
• Condensed Matter Physics
• Physical Chemistry

Background:

• Understanding the structure of high-temperature liquids is crucial for predicting their physical properties, such as fragility.
• Zirconium dioxide (ZrO2) is a non-glass-forming oxide liquid at high temperatures, making its structural analysis challenging.

Purpose of the Study:

• To elucidate the atomistic and electronic structure of high-temperature liquid ZrO2.
• To correlate the observed structure with its physical properties, including viscosity and fragility.

Main Methods:

• Analysis of the Bhatia-Thornton number-number structure factor.
• Characterization of atomic coordination polyhedra (ZrO5, ZrO6, ZrO7).
• Investigation of polyhedral connectivity and bond lifetimes.

Main Results:

• The Bhatia-Thornton structure factor of liquid ZrO2 lacks a first sharp diffraction peak.
• The atomic structure features a variety of coordination numbers for oxygen around zirconium and significant edge-sharing of oxygen polyhedra.
• Short Zr-O bond lifetimes and large zirconium ionic radius disrupt intermediate-range ordering, leading to a reduced electronic band gap and delocalized Zr-O bonding.

Conclusions:

• Liquid ZrO2 exhibits an extremely fragile nature due to its disordered atomic and electronic structure.
• The structural characteristics, including polyhedral arrangements and bonding, explain the liquid's exceptionally low viscosity and the absence of a first sharp diffraction peak.