Chen Lan, Xu Changsong, Tian Hao, Xiang Hongjun, Íñiguez Jorge, Yang Yurong, Bellaiche L
Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA.
National Laboratory of Solid State Microstructures, Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, China.
Phys Rev Lett. 2019 Jun 21;122(24):247701. doi: 10.1103/PhysRevLett.122.247701.
Controlling the direction of the magnetization by an electric field in multiferroics that are both ferroelectric and strongly ferromagnetic will open the door to the design of the next generation of spintronics and memory devices. Using first-principles simulations, we report that the discovery that the PbTiO_{3}/LaTiO_{3} (PTO/LTO) superlattice possesses such highly desired control, as evidenced by the electric-field-induced rotation of 90° and even a possible full reversal of its magnetization in some cases. Moreover, such systems also exhibit Jahn-Teller distortions, as well as orbital orderings, that are switchable by the electric field, therefore making PTO/LTO of importance for the tuning of electronic properties too. The origin for such striking electric-field controls of magnetization, Jahn-Teller deformations, and orbital orderings resides in the existence of three different types of energetic coupling: one coupling polarization with antiphase and in-phase oxygen octahedral tiltings, a second one coupling polarization with antiphase oxygen octahedra tilting and Jahn-Teller distortions, and finally a biquadratic coupling between antiphase oxygen octahedral tilting and magnetization.
在兼具铁电性和强铁磁性的多铁性材料中，通过电场控制磁化方向将为下一代自旋电子学和存储设备的设计打开大门。利用第一性原理模拟，我们报告了PbTiO₃/LaTiO₃（PTO/LTO）超晶格具有这种高度期望的控制能力这一发现，这在某些情况下表现为电场诱导的90°旋转，甚至可能使磁化完全反转。此外，这类系统还表现出可通过电场切换的 Jahn - Teller 畸变以及轨道有序性，因此PTO/LTO对于调节电子性质也很重要。这种对磁化、Jahn - Teller 变形和轨道有序性的显著电场控制的起源在于存在三种不同类型的能量耦合：一种是将极化与反相和同相氧八面体倾斜耦合，第二种是将极化与反相氧八面体倾斜和 Jahn - Teller 畸变耦合，最后是反相氧八面体倾斜与磁化之间的双二次耦合。
