AP Seminar - Two-dimensional Element Ferroelectricity with Large Negative Piezoelectric Coefficients and Intrinsically Stable Charged Domain Walls
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Date
04 Oct 2024
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Organiser
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Time
14:00 - 15:00
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Venue
CD620, 6/F, Wing CD, PolyU Map
Speaker
Prof. Yunhao Lu
Summary
Ferroelectric materials, particularly ferroelectricity in two-dimensional systems, have attracted significant interest over the past few years. However, nearly all reported ferroelectric materials are compounds composed of different types of atoms. Recently, despite being counterintuitive, we reveal spontaneous polarization and ferroelectricity in two-dimensional elemental group-V materials with a buckled lattice structure similar to black phosphorus, based on first-principles calculations and confirmed by experimental measurement. Additionally, we develop a general model to understand and search for potential two-dimensional ferroelectric and antiferroelectric materials. Using this model, we also discover that ferroelectric and antiferroelectric phases can exist in group-IV and group-VI elemental two-dimensional systems. More importantly, two-dimensional element ferroelectric materials exhibit anomalous negative piezoelectric coefficients and intrinsically stable charged domain walls, making them promising candidates for ultrathin ferroelectric devices with broad application prospects. The conclusions drawn from the study of elemental ferroelectric systems suggest the possibility of realizing unconventional ferroelectric effects in other ferroelectric systems, holding great potential for experimental realization and practical applications.
Keynote Speaker
Prof. Yunhao Lu
Professor
School of Physics
Zhejiang University
Lu Yunhao is a professor at the School of Physics, Zhejiang University. He graduated with a bachelor's and doctoral degree in Physics from Zhejiang University in 2003 and 2008. During this period, he went to the National University of Singapore for joint training. Later, he joined the Computational Physics Research Group of the National University of Singapore as a postdoctoral and senior research assistant. In 2010, he joined Zhejiang University. His primary research focuses on using first-principles methods to explore the physical properties of materials, with the goal of uncovering their universal significance and designing new functional materials. As the first or corresponding author, he has published 81 SCI papers in prestigious journals, including Nature, Nature, Nature, Nature, and Nature. Six of these papers have been recognized as highly cited in their respective fields by SCI, with total citations exceeding 12,000 and an H-index of 52. Additionally, he holds three granted invention patents.