报告题目：Charge Stabilized Ferroelectric phase of HfO₂ and Interlayer- Polarization Effects on topological transport properties of MnBi₂Te₄

报告内容简介：

Ferroelectric materials have a spontaneous electric polarization that can be switched between two or more orientations with an applied electric field. They enable devices such as nonvolatile random-access memories, ferroelectric field-effect transistors, and ferroelectric tunnel junctions. The discoveries of ferroelectricity in HfO₂, and sliding ferroelectricity in Van der Waals (VDW) materials are both attractive as they can be integrated with Si relatively easily, and provide an extra avenue to tailor magnetic orders as well as topological transport properties. However, the ferroelectric phase of HfO₂ is metastable, and it can only be stabilized on proper substrates or under specific growth conditions. Here, we will show that charge redistribution in HfO₂ can efficiently modulate the relative stabilities of its polar and non-polar phases, and hole doping contributes to stabilize polar phase of HfO₂^1-3. Furthermore, we will show that out-of-plane polarization that can be achieved in VDW materials through interlayer sliding. Even the sliding polarization is relatively week (0.01 μC/cm₂), it determines the direction anomalous hall current in even-layer MnBi₂Te₄, and can make odd-layer MnBi₂Te₄ magnetic topological insulator or trivial insulators⁴.

1. Tengfei Cao*, Guodong Ren, Ding-Fu Shao, Evgeny Y. Tsymbal *, and Rohan Mishra*, Stabilizing polar phases in binary metal oxides by hole doping, Phys. Rev. Mater. 7, 044412 (2023).

2. Saúl Estandí^#*, Tengfei Cao^#, Rohan Mishra^*, Florencio Sánchez and Jaume Gazquez, Insights into the Atomic Structure of the Interface of Ferroelectric Hf_0.5Zr_0.5O₂ grown epitaxially on La_2/3Sr_1/3MnO₃, Phys. Rev. Mater. 5(7), 074410 (2021).

3. Shu Shi^#, Haolong Xi^#, Tengfei Cao^#, Weinan Lin, Zhongran Liu, Jiangzhen Niu, Da Lan, Chenghang Zhou, Jing Cao, Hanxin Su, Tieyang Zhao, Ping Yang, Yao Zhu, Xiaobing Yan*, Evgeny Y. Tsymbal*, He Tian* & Jingsheng Chen*, Interface-engineered ferroelectricity of epitaxial Hf_0.5Zr_0.5O₂ thin films, Nat. Commun. 14, 1780 (2023).

4. Tengfei Cao*, Ding-Fu Shao*, Kai Huang, Gautam Gurung, Evgeny Y. Tsymbal* , Switchable Anomalous Hall Effects in Polar-Stacked 2D Antiferromagnet MnBi₂Te₄, Nano. Lett. 23, 3781 (2023).

报告人姓名：曹腾飞

报告人简介：

曹腾飞，教授，2014年博士毕业于中国科学院固体物理研究所凝聚态物理专业。此后出国留学，先后在纽约城市大学、圣路易斯华盛顿大学以及内布拉斯加大学以博士后或研究员的身份从事研究工作，2023年1月全职加入西北工业大学材料学院。研究领域涉及纳米材料的非线性力学性质、铁电性以及磁性拓扑等，共发表学术论文33篇，被Nat. Rev. Mater., Nat. Nanotechnol., Nat. Commun.等期刊累计引用865 多次，单篇最高他引达157次。以第一/通讯作者身份发表学术论文17篇，其中影响因子>9的论文9篇，包括1篇Phys. Rev. Lett.（一作，影响因子：9.16)、1篇Nat. Nanotechnol.（共一，影响因子：39.21）、2篇Nat. Commun.（共一，影响因子：14.92）和1篇Nano Lett（一作，影响因子：18.81)等。研究成果被众多国际报刊所报道，其中包括以报道科学、技术方面最新发现为特色的《Science Daily》、英国发行量最大报纸之一的《Daily Mail》和美国三大新闻周刊之一的《News Week》等。

报告人单位：西北工业大学 材料学院先进润滑与密封材料研究中心

报告时间：2023-11-01 9:30

报告地点：材料楼520

主办单位：上海大学

联系人：王达