We have developed a software package, namely, PASP (Property Analysis and Simulation Package for materials), to analyze the structural, electronic, magnetic, and thermodynamic properties of complex condensed matter systems. Our package integrates several functionalities including group theory analysis, global structure searching methods, tight-binding approach, machine learning algorithms, effective Hamiltonian methods, Monte Carlo simulation, and spin-lattice dynamic simulation methods. In conjunction with first-principles calculations, PASP has been successfully applied to diverse physical systems. For example, we predict that a Pb-free hybrid organic-inorganic perovskite N(CH₃)₄SnI₃ with non-polar molecular cation has strong ferroelectricity, find that there may exist high-order spin interactions in 2D materials, propose a general theory for bilayer stacking ferroelectricity, propose the concept of unconventional ferroelectricity in violation of Neumann's principle.

Hongjun Xiang is a professor in the Department of Physics at Fudan University and a recipient of the Distinguished Young Scholars Fund from National Natural Science Foundation of China. He is also a Chief Scientist in the Key Research and Development Program of the Ministry of Science and Technology. From 1997 to 2006, he studied at the University of Science and Technology of China, where he obtained his Bachelor's and Ph.D. degrees. From 2006 to 2009, he conducted postdoctoral research at North Carolina State University and the National Renewable Energy Laboratory in the United States.

Prof. Xiang's research focuses on computational condensed matter physics, with significant contributions in the establishment of models for multiferroic systems and the development of computational methods. Some of his notable achievements include proposing a unified model for spin-order induced ferroelectricity, which surpasses the limitations of traditional models and provides a general physical understanding of a broad class of multiferroic materials, gaining recognition from experts in the field. He has also developed the four-state method for calculating magnetic interactions and magneto-electric coupling strength, which has been widely adopted by research groups both domestically and internationally. Using these models and methods, he has explained the origin of ferroelectricity in multiferroic materials, discovered new mechanisms of magneto-electric coupling, and designed high-performance multiferroic materials. Prof. Xiang has also contributed to the development of the materials analysis and simulation software package PASP, which has been commercialized and adopted by numerous research groups worldwide. He has published over 200 research papers, including 34 in Physical Review Letters, as the first or corresponding author. His research work has been published in renowned journals such as Physical Review Letters, Nature Materials, Nature Communications, and Physical Review X. Since 2014, he has been recognized as a Highly Cited Researcher in China by Elsevier. In 2018, he received the International Center for Theoretical Physics (ICTP) Prize from Italy, and in 2021, he was elected as a Fellow of the American Physical Society (APS). In 2023, he was awarded the Huang Kun Physics Prize.

Please contact phweb@ust.hk should you have questions about the talk.