Sublattice Melting in Binary Superionic Colloidal Crystals

TL;DR

This study reveals sublattice melting in colloidal crystals with asymmetric charged particles, leading to superionic phases with unique non-electroneutral structures and tunable stoichiometries, advancing understanding of ionic conduction in colloidal systems.

Contribution

It demonstrates sublattice melting in colloidal crystals with asymmetric particles, showing formation of superionic phases with non-electroneutral stoichiometry and domain structures.

Findings

Small particles melt at higher temperatures forming superionic phases.

Crystals exhibit non-electroneutral stoichiometric ratios.

Structures contain multiple ionic crystal domains.

Abstract

In superionic compounds one component pre-melts providing high ionic conductivity to solid state electrolytes. Here, we find sublattice melting in colloidal crystals of oppositely charged particles that are highly asymmetric in size and charge in salt solutions. The small particles in ionic compounds melt when the temperature increases forming a superionic phase. These delocalized small particles in a crystal of large oppositely charged particles, in contrast to superionic phases in atomic systems, form crystals with non-electroneutral stoichiometric ratios. This generates structures with multiple domains of ionic crystals in percolated superionic phases with adjustable stoichiometries.