Prediction of Novel Li-AgII-F Compounds using Evolutionary Algorithms

TL;DR

This paper uses evolutionary algorithms to predict new Li-Ag-F compounds, analyzing their stability and magnetic properties, revealing potential for synthesis and exceptionally strong magnetic interactions in certain structures.

Contribution

It introduces a computational approach to predict novel Li-Ag-F compounds and their magnetic behaviors, highlighting a compound with record-breaking superexchange interaction.

Findings

Predicted structures are slightly above the phase separation line but may be synthesizable.

All structures favor antiferromagnetic ground states.

LiAgF3 type2 exhibits an exceptionally large superexchange constant of -358 meV.

Abstract

This work provides a theoretical exploration of the thermodynamic stability and magnetic behaviour of previously unknown ternary Li AgII F compounds. Convex-hull analysis shows that all predicted structures lie slightly above the LiF plus AgF2 decomposition line, indicating a natural tendency toward phase separation; nevertheless, their negative formation energies relative to AgF, LiF, and F2 or F suggest that alternative synthetic pathways may be feasible for these compounds. All studied structures show preference for antiferromagnetic ground state. Notably, the triclinic LiAgF3 type2 is predicted to exhibit an exceptionally large superexchange constant, J equal to minus 358 meV, within Ag2F7 dimers, placing it above the strongest known magnetic exchange interactions reported to date.