报告题目：A live view on surface restructuring at realistic conditions via replica-exchange grand-canonical method

报告人：周院院， Leibniz Institute Berlin Junior group leader

报告时间：2023年12月29日 14：00

报告地点：威利斯游戏网站中心校区唐敖庆楼B区521报告厅

个人简介

　　Dr. Yuanyuan Zhou received her B. S. in Physics from Jilin University in 2012. Then she joined Prof. Yanming Ma’s group and completed her M. S. in Condensed Matter Physics in Jilin University in 2015. Afterwards, Dr. Zhou moved to Berlin Germany, studied in Frits Haber Institute working with Prof. Luca M. Ghringhelli and Prof. Matthias Scheffler, and defended her Ph.D. thesis in 2020 with the highest possible distinction: summa cum laude in Theoretical Physics. Since 2021, Dr. Zhou worked as postdoctoral fellow with Prof. Jens K. Nørskov and closely collaborated with Prof. Ib Chorkendorff in Technical University of Denmark. She will start the junior group leader position in Leibniz Institute Berlin, Germany.

　　Dr. Zhou’s research mainly focuses on method development for surface material under realistic condition modelling based on statistical mechanics and statistical learning from the atomistic process up to the entire reactor. Her goal is to understand the mechanisms that underlie the macroscopic performance of surface materials and improve them through rational design, e.g., semiconductor thin film and electrocatalyst.

报告简介

　　The processes occurring at surfaces play a critical role in the manufacture and performance of advanced materials , e.g., semiconductor thin film crystal growth and electrochemical catalysis. Therefore, knowledge of the morphology and structural evolution of material surfaces under realistic conditions is a prerequisite for understanding the mechanism of, e.g., semiconductor crystal growth and electrocatalysis due to the structure-property-performance relationship.

　　In this talk, I will introduce our developed replica-exchange grand-canonical (REGC) method[1] that enables an accurate determination of surface phase diagram and dynamical description of surface restructuring under operation conditions. This benefits from the unbiased sampling of the compositional and configurational phase space. Specifically, I will take three application systems as examples to illustrate the predictive power of the REGC approach: (1) The approach is demonstrated by addressing open questions for the Si(100) surface in a hydrogen gas phase[2]. By defining microscopic descriptors, 25 distinct thermodynamically stable surface phases are identified, most of which including few order-disorder phase transitions, have not been observed experimentally, so far. The results also show that Si-Si-bonds forming/breaking is the driving force behind the phase transition between the experimentally confirmed 3×1 and 2×1 adsorption patterns. (2) we also revealed the mechanism why the most active hydrogen oxidation reaction (HOR) catalyst Pt in the aqueous condition cannot work in the organic solvent. However, by introducing Au into Pt, the Pt undergoes the surface segregation and stabilizes into Pt/Au. The strain effect between the Pt overlayer and Au substate maintains the HOR activity but also suppresses CO poison of the catalyst[3]. (3) The REGC method is also applied to identify the reconstruction of Ga2O3 surfaces in the thin film crystal growth via molecular beam epitaxy, which is also oberved in experiment..

[1] Y. Zhou, M. Scheffler, and L. M. Ghringhelli., Phys. Rev. B. 100, 174106 (2019).

[2] Y. Zhou, C. Zhu, M. Scheffler, and L. M. Ghringhelli., Phys. Rev. Lett. 128, 246101 (2022).

[3] X. Fu+, J. B. Pedersen+, Y. Zhou+, et al. J. K. Nørskov, and I. Chorkendorff., Science. 379, 707 (2023).

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