时间：2025年6月12日下午14:00-15:30

Time: 14:00-15:30, Thursday, June 12, 2025

主持人：西湖大学理学院物理系PI 刘仕

Host: Dr. Shi Liu, PI of School of Science, Westlake University

地点：云谷校区E10-211

Venue: E10-211, Yungu Campus, Westlake University

报告语言：英文

Lecture Language: English

Prof. Jun Hee Lee,

School of Energy & Chemical Engineering/Graduate School of Semiconductor Materials & Engineering, 

Ulsan National Institute of Science and Technology, South Korea

主讲人/Speaker:

Jun Hee Lee is a full professor in Ulsan National Institute of Science and Technology (UNIST) in South Korea. He obtained Ph.D. in condensed matter physics from Seoul National University in Korea. Then he moved to USA and carried on postdoc research at Rutgers University (Physics), Princeton University (Chemistry) and Oak Ridge National Laboratory (Materials Science). Since 2015, he came to UNIST as an assistant, associate and full professor in School of Energy & Chemical Engineering/Graduate School of Semiconductor Materials & Engineering. Thanks to his interdisciplinary backgrounds, he has been working on various fields such as ferroelectric/multiferroic, battery, solar cell, triboelectric and H2-generation catalysts.

讲座摘要/Abstract:

Ferroelectric HfO₂ has emerged as a promising candidate for next-generation memory semiconductor due to its scalability and compatibility with CMOS technology. Unlike traditional ferroelectrics whose phonon energy bands disperse, we discovered that the bands of HfO₂ are remarkably flat and enables it unit-cell-by-unit-cell ferroelectric switching even at the sub-nanoscale [1], making it ideal for ultimately high-density storage. Thanks to the smallest ferroelectric domains even smaller than the unit-cell, recently we additionally discovered that sub-picosecond record-fast switching is possible by the THz light pulse [2]. This will open the era of future electronic devices employing non-contact, leakage-free, and ultrafast ferroelectric switching operation. If time permits, we will talk about various other ferroelectric domain walls in this compound including head-to-head [3] and present how to engineer their beneficial effects by doping [4] and hetero structuring [5]. Finally, we will demonstrate its potential for ultrafast, high-density, and energy-efficient in-computing memory architectures, paving the way for next-generation computing systems.

[1] "Scale-free ferroelectricity induced by flat phonon bands in HfO2", Science, 369, 1343 (2020)

[2] "Real-time sub-picosecond switching of ferroelectric polarization", (In review)

[3] "Negative gradient energy stabilzed charged domain walls in HfO2", Physical Review Letters, 134, 166101 (2025)

[4] "Doping engineering to reduce the coercive field of ferroelectric ZrO2", Physical Review Applied, 22, 064039 (2024)

[5] "Hybrid-improper ferroelectricity in a Si-compatible HfO2/CeO2 superlattice", NPJ Comput. Mater. 10, 294 (2024)

讲座联系人/Contact:

School of Science, Yanyan Chen, Email: chenyanyan@westlake.edu.cn