Interface control of ferroelectricity in LaNiO3-BaTiO3 superlattices

TL;DR

This study uses first-principles calculations to show how interface types in LaNiO3-BaTiO3 superlattices influence ferroelectricity, revealing that polar discontinuities at interfaces can enhance ferroelectric properties.

Contribution

The paper demonstrates how different interface terminations in LaNiO3-BaTiO3 superlattices affect ferroelectricity, highlighting the role of polar discontinuity in tuning ferroelectric behavior.

Findings

Enhanced ferroelectricity with (NiO$_2$)$^-$/(BaO)$^0$ interfaces

Polar discontinuity causes hole localization and electron penetration

Potential for robust ferroelectricity in ultrathin BaTiO$_3$ films

Abstract

LaNiO$_{3}$-BaTiO$_{3}$ superlattices with different types of interfaces are studied from first-principles density-functional theory. It is revealed that the ferroelectricity in the superlattice with (NiO$_2$)$^-$/(BaO)$^0$ interfaces is enhanced from that of the superlattice with (LaO)$^+$/(TiO$_2$)$^0$ interfaces. The origin lies at the polar discontinuity at the interface, which makes the holes localized within the (NiO$_2$)$^-$/(BaO)$^0$ interface, but drives a penetration of electrons into BaTiO$_3$ component near (LaO)$^+$/(TiO$_2$)$^0$ interface. Our calculations demonstrate an effective avenue to the robust ferroelectricity in BaTiO$_3$ ultrathin films.