Interfacial Multiferroics of TiO₂/PbTiO₃ Heterostructure Driven by Ferroelectric Polarization Discontinuity

Abstract

Novel phenomena appear when two different oxide materials are combined together to form an interface. For example, at the interface of LaAlO/SrTiO, two-dimensional conductive states form to avoid the polar discontinuity, and magnetic properties are found at such an interface. In this work, we propose a new type of interface between two nonmagnetic and nonpolar oxides that could host a magnetic state, where it is the ferroelectric polarization discontinuity instead of the polar discontinuity that leads to the charge transfer, forming the interfacial magnetic state. As a concrete example, we investigate by first-principles calculations the heterostructures made of ferroelectric perovskite oxide PbTiO and nonferroelectric polarized oxide TiO. We show that charge is transferred to the interfacial layer forming an interfacial ferromagnetic ordering that may persist up to room temperature. Especially, the strong coupling between bulk ferroelectric polarization and interface ferromagnetism represents a new type of magnetoelectric effect, which provides an ideal platform for exploring the intriguing interfacial multiferroics. The findings here are important not only for fundamental science but also for promising applications in nanoscale electronics and spintronics.

Selective Chemical Epitaxial Growth of TiO2 Islands on Ferroelectric PbTiO3 Crystals to Boost Photocatalytic Activity

“…So far, many bare ferroelectric semiconductors and their composites with unique charge transport behaviors have been investigated for enhanced photocatalytic or photoelectrochemical reaction activities. [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] Developing such ferroelectric-based photocatalysts is therefore anticipated to address the challenge of the low-efficiency charge separation that most common photocatalysts have, and this is considered a vital step of the three distinct steps in photocatalysis (light absorption, charge separation, and surface catalysis reaction). [40][41][42][43][44][45][46][47] Photocatalysts for water splitting to produce H 2 , or for CO 2 reduction to produce high-value chemicals, usually consist of semiconductors as a light absorber and co-catalysts as both the collector and reaction center of the photogenerated charges.…”

Polarization Screening Mechanisms at La0.7Sr0.3MnO3–PbTiO3 Interfaces

“…By altering the electronic and mechanical boundaries, 5,[11][12][13] new functional properties such as conduction and magnetism can emerge. [14][15][16][17] This has empowered the development of novel ferroelectric based nanoelectronic devices. Many parameters at the interface (such as strain, conductivity and composition) can influence the observed polarisation, 5,18 which are often competing and provide a complex array of options to engineer desired properties.…”

Thickness Control of the Spin-Polarized Two-Dimensional Electron Gas in LaAlO3/BaTiO3 Superlattices

“…In order to ensure the reliability of the relationship between interfacial charge carrier density and the parameter n, we also calculated local magnetic moment 29 , 33 , 36 on Ti atoms of the interfacial TiO 2 monolayer. From Fig.…”