Interplay between Ferroelectricity and Metallicity in BaTiO${}_3$

Abstract

We explore the interplay between ferroelectricity and metallicity, which are generally considered to be contra-indicated properties, in the prototypical ferroelectric barium titanate, BaTiO${}_3$. Using first-principles density functional theory, we calculate the effects of electron and hole doping, first by introducing a hypothetical background charge, and second through the introduction of explicit impurities (La, Nb and V for electron doping, and K, Al and Sc for hole doping). We find that, apart from a surprising increase in polarization at small hole concentrations, both charge-carrier types decrease the tendency towards ferroelectricity, with the strength of the polarization suppression, which is different for electrons and holes, determined by the detailed structure of the conduction and valence bands. Doping with impurity atoms increases the complexity and allows us to identify three factors that influence the ferroelectricity: structural effects arising largely from the size of the impurity ion, electronic effects from the introduction of charge carriers, and changes in unit-cell volume and shape. A competing balance between these contributions can result in an increase or decrease in ferroelectricity with doping.

References in corpus (5)

• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
• Non-$d^0$ Mn-driven ferroelectricity in antiferromagnetic BaMnO${}_3$
• Ferroelectric Instability under Screened Coulomb Interactions
• Local structural origins of the distinct electronic properties of Nb-substituted SrTiO${}_3$ and BaTi$O_3$

Cited by in corpus (10)

• Structural Polymorphism Kinetics Promoted by Charged Oxygen Vacancies in HfO${}_2$
• Polar Metals Taxonomy for Materials Classification and Discovery
• Emergent superconductivity in doped ferroelectric hafnia
• Ferroelectric Polarization Reversal vs Pump Spot Shape
• Mechanism for Switchability in Electron-Doped Ferroelectric Interfaces
• Quantum fluctuation of ferroelectric order in polar metals
• Pressure-induced metal-insulator transition in oxygen-deficient LiNbO${}_3$-type ferroelectrics
• Point defect design in (Ba,Sr)TiO${}_3$ -- an insight on agglomeration
• Coupling between small polarons and ferroelectricity in BaTiO3
• Ultrafast non-thermal suppression of ferroelectricity by carrier screening in LiNbO3