多铁性材料BiFeO_3超结构的量子衍生现象

Emergent Phenomena at Multiferroic BiFeO_3 Superstructures

在过去的十余年时间里,多铁材料所蕴含的丰富多彩的物理特性以及广泛的应用前景引起了人们的广泛关注。其中模型室温多铁材料BiFeO3(BFO)因其卓越的铁电特性以及所伴随的室温反铁磁特性而成为多铁领域的明星材料,受到凝聚态物理以及材料科学家的格外青睐。研究人员围绕着BFO的结构、铁电、磁学以及磁电耦合等特性开展了一系列开创性的研究。而BFO也成为了进行受限尺度量子调控研究的模型体系,形成了异质界面、畴壁、相界以及纳米结构等多种超结构体系。本文将着重介绍由多铁性材料BFO所构成的这一系列丰富多彩的超结构体系中,因为量子受限作用所表现出的衍生现象以及功能特性。在着重介绍BFO超结构的磁电耦合特性的同时,本文还将介绍该系列超结构所体现出的输运、光电、压电等功能特性。文章最后,笔者还将就多铁性材料超结构领域的研究前景进行展望。

In the past decade, multiferroic materials have attracted extensive research interests due to the rich physics involved and promising potential applications. Being the prototype room temperature multiferroic, BiFeO3 （BFO） becomes one of the focal points for the condensed matter physics and materials science studies, particularly due to its prominent ferroelectric properties and above room-temperature antiferromagnetic transition temperature. Researchers have carried out a series of seminal studies with great attentions to the structure, ferroelectric, magnetic and magnetoelec- tric properties of this ＂star material＂. BFO also becomes a model system to study the emergent phenomena at the quantum-confined superstructures, such as heterointerface, ferroelectric domain wall, structure phase boundary, nano-pillar, superlattice and so on. In this paper, we review the recent studies on the understanding of novel functionalities formed at a series of BFO superstruc- tures due to the quantum confinement effects. We focus on not only the magnetoelectric coupling at the BFO superstructures, a central question of multiferroic studies, but also the other function- alities, such as local transport, photovoltaic, piezoeleletric, etc. We summarize by highlighting several possible and promising direction for the future studies of multiferroic superstructures.