Prof. Anatoly Belonoshko [南京大学]

Title: Current Problems in Studies of Iron under Extreme Conditions 

Time: 10:00- 11:00, Feb. 22, 2024

Place: 6-410, Shanghai Lecture Hall of HPSTAR；

Online:  https://meeting.tencent.com/dm/xRmFpMOQe8WL

#Meeting ID：170-915-870

Language: English

Host: Dr. Duckyoung Kim

Abstract:

Iron (Fe) is a major component of the Earth and inhabited exoplanets cores, yet its phase diagram at extreme pressures (P) and temperatures (T) is a subject of extensive debate. Since the solid core is at the temperature close to melting it is of ultimate importance to know the structure of the sub--melting phase. Such knowledge enables understanding of the planet evolution from the beginning to the current state and predicting the future. While recent experiments provide the evidence for the stability of the body-centered cubic ($\it{bcc}$) phase, several theoretical studies point to the stability (even though marginal) of the hexagonal close--packed phase. None of those studies considered the itinerant magnetism of iron at extreme conditions. We computed the melting curves using the density functional theory based molecular dynamics (DFT MD) with and without thermally induced longitudinal spin fluctuations (LSF). The non-magnetic DFT MD simulations result in stability of the hcp as the submelting phase with 8 and 16 valence electrons while the bcc phase stabilizes for the case of 14 valence electrons. The LSF DFT MD with 16 valence electrons favors the bcc phase stability. Therefore, we conclude that the account of magnetism results in the new physics of iron at extreme conditions and brings the theory in agreement with experiment.

Personal Bio:

He was born in Soviel Union. He gradualed from Moscow State University in the field of Mechanical Engineering and then worked at the USSR Academy of Sciences. After defending his dissertation at the Institute of Chemical Physics in Moscow, he received a postdoc-position at the Institute of Earth Sciences of Uppsala University and continued his research at Uppsala University at the Department of Physics. He went to Nanjing University as professor since April 2023. His research interests are in applying computational method to study materials under extreme conditions, in particular minerals in the deep interior of the Earth. He published more than 100 papers (among them are papers in Nature Science,Nature Geoscience, PRL elc) in this field. His research on the Earth inner Core was highlighted by Swedish and international media, For his studies he was elected as a fellow of American Physics Society.