钙钛矿型铁电氧化物表面结构与功能的控制及其潜在应用

Control of surface structures and functionalities in perovskitetype ferroelectric oxides and their potential applications

钙钛矿型铁电氧化物由于具有本征的、非易失的、可翻转的自发极化以及带有高电荷密度的极性表面等特性,被认为是最有前途的功能材料之一.研究钙钛矿型铁电氧化物的表面结构对理解其表面/界面能量转化、调控表面物质吸附和脱附、控制界面化学反应、以及设计稳定的低功耗电子器件具有重要意义.本文首先概述了铁电相与其表面结构的关系,并介绍了钙钛矿型铁电氧化物复杂表面结构的形成;之后阐述了铁电表面/界面结构的调控机制,为后续的钙钛矿型铁电氧化物的表面结构设计、表面性能与功能的控制提供了研究基础;最后介绍了铁电氧化物表面/界面的功能调控和潜在器件的设计,并结合目前铁电材料领域表面科学研究的局限性,对今后基于钙钛矿型铁电氧化物表面结构的研究发展以及应用前景提出了展望.

Over the past decades,exploration and artificial control of the surface and interfacial structure of the materials have played an important role in chemical catalyzing,energy conversion,information storage and medical field,and thus the finding of suitable materials with controllable surface/interface properties has attracted intense interest in recent years.Perovskite-type ferroelectric oxides are considered to be one of the most promising functional materials due to their intrinsic,non-volatile,reversible spontaneous polarization and controllable polar surface with high charge density.The investigating of the interaction between polarization and surface structure of perovskite-type ferroelectric oxide is very important for understanding the surface(interface)energy conversion,regulating the adsorption and desorption on the surface,controlling interfacial chemical reaction,and designing stable low-power electronic devices.In this paper,we summarize the theoretical mechanism and potential applications of the surface structures and functionality in perovskite-type ferroelectric oxide from three aspects.Firstly,we describe the inseparable relationship between the stabilized ferroelectric phase and surface structure of ferroelectric material,and illustrate the formation mechanism of complex surface structure of perovskite-type ferroelectric oxide.In order to reduce the surface energy to stabilize the polar surface of the material,perovskite-type ferroelectric oxide always needs to absorb foreign charged particles,change the stoichiometry and conduct electron orbital hybridization or surface relaxation,etc.,which will cause the complexity of the surface structure of ferroelectric.Secondly,we outline the influence of ferroelectric polarization on the surface structure of ferroelectric and the behavior of changing ferroelectric polarization by controlling surface structure through adjusting the external environment,which provides an important basis for the subsequent regulation of the surface performance and functionality of perovskite-type ferroelectric oxide.Finally,we introduce the utilization of the controllable physical and chemical properties of ferroelectric surface(interface)into large area and into nanoscale(nanodomain),which has bright application prospects in many frontier fields,including non-volatile memory system,cell proliferation,microfluidic control system,catalysis,optical device and photodetector and so on.Furthermore,considering the limitations of current scientific research about the ferroelectric surface,we put forward the prospects for the future development of the ferroelectric material in the areas of information storage,controllable chemical reactions and new energy conversion.