时间：2021年3月18日，下午15:00-16:40

地点：主楼东配楼二层228会议室

题目：First-principles study of ferroelectricity and magnetoelectric effects in complex oxides

报告人：叶萌

联系人：朱静

摘要：

铁电材料在作为存储单元、传感器和晶体管方面有着广阔的应用。第一性原理计算在预测铁电行为方面取得了巨大的成功，加深了对极化机制的理解。本次报告将介绍铁电极化相关的重要概念以及一些重要的研究方法，并以几种典型材料为例说明第一性原理计算如何揭示铁电极化的机理。另外，报告还会以波恩有效电荷的概念作为类比，介绍动态磁电荷的概念（dynamical magnetic charge）。这一概念在理解磁电耦合机制方面有着十分重要的作用，同时报告将从理论研究出发介绍能够增强动态磁电荷，在材料中获得强磁电耦合效应的方法。

Ferroelectric (FE) materials are of fundamental interest and have broad applications as memory cells, sensors and transistors. First-principles methods have achieved great success in the prediction of polarization and have provided great insight in the understanding of FE mechanisms. In this talk, I will give a review of important concepts and methods in describing ferroelectricity and using several materials as examples to demonstrate how first-principles calculations can reveal the mechanism of ferroelectricity. In addition, I will also extend the concept of Born effective charge Ze to its magnetic analogue, the dynamical magnetic charge Zm. The concept of magnetic charges plays an important role in understanding the magnetoelectric couplings and I will present theoretical studies of the mechanisms that could enhance the magnetic charge Zm.

报告人简介：

叶萌，清华大学物理系水木学者。2011年本科毕业于中国科学技术大学，2016年获得罗格斯大学物理学博士学位，导师为David Vanderbilt教授。2016至2019年在芝加哥大学从事博士后研究，导师为Giulia Galli教授。她的研究主要聚焦于材料中极化、磁性、光学性质之间的耦合效应，特别是在铁电材料、多铁材料、固态自旋量子比特和非线性光学材料方面有着深入的研究。

Meng Ye is currently a Shuimu Tsinghua Scholar in the physics department of Tsinghua University. She graduated from the University of Science and Technology of China in 2011 and received her Ph.D degree in physics from Rutgers University under the supervision of Professor David Vanderbilt in 2016. After that, she went to the University of Chicago to work with Prof. Giulia Galli as a postdoc scholar from 2016 to 2019. She has broad interests in theoretical and computational condensed matter physics. Her research is focused on the cross-coupling of polarization, magnetization and light in materials, especially in ferroelectrics, multiferroics, solid state spin qubits and non-linear optical materials.