报告题目：Light control of phase transitions

报告人：孟胜研究员，中科院物理所

报告时间：2024年7月8日（星期一）下午3：00-4：00

报告地点：致知楼会议室3328

报告摘要：

Photoexcitation is a powerful means in distinguishing different interactions and manipulating the states of matter, especially in phase transitions in complex quantum systems. Here we demonstrate photoexcitation induced ultrafast phase transition dynamics in prototypical quantum materials, using newly developed time-dependent density functional theory quantum molecular dynamics methods incorporating both nonadiabatic effects and nuclear quantum effects. In particular, we discover a novel phase inversion mechanism in the charge density wave (CDW) of TiSe₂, and a collective pathway from 2H phase to 1T phase in MoTe₂ induced by photoexcitation which is significantly different from thermal phase transitions. We will also discuss photoinduced electronic phases in other materials such as controlling the dynamics of Weyl quasiparticles in semimetal WTe₂, insulator-to-metal transitions mediated by electron correlations in VO₂, and ultrafast plasma generation in liquid water. Our results provide insights from a new perspective on the coherent electron and lattice quantum dynamics in materials upon photoexcitation

报告人简介：

孟胜，中科院物理所研究员、国科大岗位教授、表面物理国家重点实验室主任，国家重点研发计划项目首席科学家。2000年中国科技大学毕业，2004年获中科院物理所凝聚态物理博士学位，同年获瑞典Chalmers 理工大学应用物理博士学位。2005-2009年在哈佛大学物理系任博士后。主要从事凝聚态体系的非平衡态超快量子动力学研究，发表论文300余篇，荣获2012年基金委优秀青年基金，2012年国际材料联合会青年科学家银奖，2015年入选中组部青年拔尖人才计划，2019年获教育部自然科学一等奖、北京市科技一等奖，2020年获得国家杰出青年科学基金支持。