Unusual Metallic Multiferroic Transitions in Electron-Doped PbTiO3
Unusual Metallic Multiferroic Transitions in Electron-Doped PbTiO3
复制标题
电子掺杂 PbTiO3 中不寻常的金属多铁性转变
DOI：
10.1002/aelm.201700134
复制
发表时间：
2017
影响因子：
6.2
通讯作者：
Kitamura Takayuki
中科院分区：
文献类型：
--
作者：
Shimada Takahiro;Xu Tao;Araki Yasumitsu;Wang Jie;Kitamura Takayuki
作为获得非平凡物理现象和非常规多功能物质的有趣手段，一些通常处于互斥状态的材料的共存引起了人们的极大关注。尽管具有铁电、磁性和光学多功能的单相材料有望实现新的技术范式，但铁电、导电性和磁性之间的相互排斥机制阻碍了导电多铁体的发现。本文利用混合Hartree-Fock密度泛函理论，从理论上论证了电子掺杂PbTiO_3中铁电失真、自由载流子和磁性的可能相容性质，为金属多铁性提供了一条新的途径。由于PbTiO_3材料中独特的孤对铁电性，电子掺杂可以诱导与PbTiO_3共存的金属导电性，甚至增强铁电失真。注入的超额电子在自旋极化状态下，在垂直于极化方向的平面内相互作用，形成层状铁磁性和具有非线性磁电耦合的多铁性。这些结果表明了一种绕过传统限制的方法，导致了新型多功能材料的出现，在这种材料中，不寻常的多铁性和导电特性同时存在。
The coexistence of some materials which are normally in mutually exclusive states is attracting considerable attention as an intriguing means of obtaining nontrivial physical phenomena and unconventional multifunctional substances. Although single‐phase materials endowed with integrated ferroelectric, magnetic, and optical multifunctions hold promise for new technological paradigms, the mutually exclusive mechanisms within ferroelectricity, conductivity, and magnetism hinder the discovery of conducting multiferroics. Here, a new path toward metallic multiferroics is provided by theoretically demonstrating the possible compatible nature of ferroelectric distortion, free carriers, and magnetism in electron‐doped PbTiO3using the hybrid Hartree–Fock density functional theories. Doping with electrons is found to induce metallic conductivity that coexists with and even enhances the ferroelectric distortion in PbTiO3, due to the unique lone‐pair ferroelectricity in this material. The injected excess electrons, in spin‐polarized states, interact with one another in the plane perpendicular to the polar direction, resulting in layer‐arranged ferromagnetism and multiferroics with nonlinear magnetoelectric coupling. These results indicate a means of circumventing conventional restrictions, leading to new types of multifunctional materials in which unusual multiferroic and conductive characteristics are simultaneously present.