Novel Copper Fluoride Analogs of Cuprates

TL;DR

This study predicts new copper fluoride compounds with potential high-temperature superconductivity mechanisms similar to cuprates, based on first-principles calculations and crystal structure predictions.

Contribution

First-principles prediction of two new stable Cu-F compounds with magnetic properties and potential superconductivity, expanding the understanding of cuprate-like materials.

Findings

Predicted stable Cu2F5 and CuF3 phases.

CuF3 contains antiferromagnetically coupled Cu 3+ ions.

Doped CuF3 and Cu2F5 may exhibit high-temperature superconductivity.

Abstract

On the basis of the first-principles evolutionary crystal structure prediction of stable compounds in the Cu-F system, we predict two experimentally unknown stable phases -- Cu2F5 and CuF3. Cu2F5 comprises two interacting magnetic subsystems with the Cu atoms in the oxidation states +2 and +3. CuF3 contains magnetic Cu 3+ ions forming a lattice with the antiferromagnetic coupling. We showed that some or all of Cu 3+ ions can be reduced to Cu 2+ by electron doping, as in the well known KCuF3. Significant similarities between the electronic structures calculated in the framework of DFT+U suggest that doped CuF3 and Cu2F5 may exhibit high-temperature superconductivity with the same mechanism as in cuprates.