Biography：Dr. Kenji Mochizuki obtained his Ph.D from the School of Physical Sciences at SOKENDAI (Japan) in 2014. In 2020, he was appointed as a ZJU 100 Young Professor in the Department of Chemistry at Zhejiang University. He is a specialist in computational physical chemistry, with a research focus on ice, water, and aqueous solutions. He has an publication record, with 38 articles to his credit, including notable contributions to high-impact journals such as Nature (2013), PNAS (2015), and JACSs (2017, 2018). He received many awards, including Young Scientist Award form The Physical Society of Japan and Ikushi Prize from JSPS. His recent projects are supported by NSFC.
 

Abstract: Melt growth rate can vary widely depending on the material, ranging from 0.1 m/s for hexagonal ice (Ice Ih) to over 100 m/s for pure metals. Despite considerable research efforts, a comprehensive microscopic understanding of the factors that determine these distinct growth rates is yet to be achieved. Twenty different ice forms have been confirmed in experiments, with many more predicted by simulations. A variety of hydrogen-bond networks in those ice polymorphs imply that there is a large variation in the growth rate and ice-water interface. Actually, ice Ih is known to grow slowly on the order of 0.1 m/s. In contrast, rapid formation of ice VII on a sub-microsecond timescale has been demonstrated in dynamic compression experiments. This study applies extensive molecular dynamics simulations to examine the growth of ice VII, revealing a fast growth rate comparable to pure metals while maintaining robust hydrogen-bond networks. The results from an unsupervised machine learning applied to identify local structure suggest that the surface of ice VII consistently exhibits a body-centered cubic plastic ice layer with decoupled translational and rotational orderings. The study also uncovers the ultrafast growth rate of pure plastic ice, indicating that orientational disorder in the crystal structure may be associated with faster kinetics. Additionally, we compare the results for other ice polymorphs (ice I, III, V, and VI) that have a phase boundary with liquid water on the temperature-pressure phase diagram, allowing for a stable solid-liquid coexistence.