Ferroelectric Instability under Screened Coulomb Interactions

TL;DR

This study investigates how doping affects ferroelectricity in BaTiO3, revealing that ferroelectricity persists up to a certain doping level and is primarily driven by short-range Coulomb interactions, aligning with experimental data.

Contribution

It demonstrates that ferroelectric instability in doped BaTiO3 depends mainly on short-range Coulomb forces, providing new insights into ferroelectricity's origin and potential electronic applications.

Findings

Ferroelectric displacements persist up to 0.11 electrons per unit cell.

Ferroelectric instability relies on short-range Coulomb interactions.

Doped ferroelectrics can exhibit coexistence of ferroelectricity and conductivity.

Abstract

We explore the effect of charge carrier doping on ferroelectricity using density functional calculations and phenomenological modeling. By considering a prototypical ferroelectric material, BaTiO3, we demonstrate that ferroelectric displacements are sustained up to the critical concentration of 0.11 electron per unit cell volume. This result is consistent with experimental observations and reveals that the ferroelectric phase and conductivity can coexist. Our investigations show that the ferroelectric instability requires only a short-range portion of the Coulomb force with an interaction range of the order of the lattice constant. These results provide a new insight into the origin of ferroelectricity in displacive ferroelectrics and open opportunities for using doped ferroelectrics in novel electronic devices.