- Speaker
- A/Prof. Lei Zhang
- Peking University
- Abstract
Despite the fact that tremendous efforts have been made on the study of quasicrystals since their discovery in 1984, nucleation of quasicrystals, viz. the emergence of a quasicrystal from a crystalline phase, still presents an unsolved and challenging problem. The difficulties lie in that quasicrystals and crystals are incommensurate structures in general, so there are no obvious epitaxial relations between them. In this talk, we proposed a saddle dynamics method to solve this problem by applying the Landau theory of phase transitions. We obtained the accurate critical nuclei and transition pathways connecting crystalline and quasicrystalline phases. The results reveal that phase transitions between the crystalline and quasicrystalline phases could follow two possible pathways, corresponding to a one-stage phase transition and a two-stage phase transition involving a metastable lamellar quasicrystalline state, respectively. The proposed computational methodology not only reveals the mechanism of nucleation of quasicrystals, but also paves the way to investigate a wide range of physical problems undergoing the first-order phase transitions.
- About the Speaker
张磊,北京大学北京国际数学研究中心长聘副教授/研究员,国际机器学习中心、定量生物学中心PI。2009年在美国宾州州立大学数学系获博士学位。研究领域为计算和应用数学,包括稀有事件与解景观的算法与应用,计算材料科学,计算系统生物学等。研究成果在Phys. Rev. Lett.、PNAS、Acta Numerica、Science子刊、Cell子刊、SIAM系列等期刊发表。曾获中组部高层次青年人才计划、基金委优秀青年基金、英国皇家学会牛顿高级学者、基金委原创探索计划项目等资助。现担任科技部重点研发计划项目首席科学家,以及SIAM J. Appl. Math, CSIAM Trans. Appl. Math, DCDS-B,The Innovation,计算数学期刊编委。
- Date&Time
- 2022-07-18 8:30 AM
- Location
- Room: Tencent Meeting