10月28日-物理学科学术报告（程丽博士，清华大学）

【报告题目】: First-Principles investigations on 1T-TaS2

【报 告 人】：程丽博士，清华大学

【报告地点】：29幢414

【报告时间】：2025年10月28日（周二），9:30

【报告摘要】：The layered transition-metal dichalcogenide 1T-TaS₂ has been intensively studied owing to its rich physics [1,2]. This talk summarizes a series of my graduate studies on this material from a first-principles perspective. First, our ab-initio Molecular dynamics simulations reproduce the commensurate charge density wave (CCDW) transition in monolayer 1T-TaS₂, reveal that the Mott gap induced by the CDW continuously decreases with increasing lattice temperature, even though the CDW amplitude remains nearly unchanged [3]. Second, the emergence of the flat band near the Fermi level is clarified by introducing a rotated t_2g orbital basis aligned with the TaS₆ octahedron. we demonstrate that inter-orbital coupling, enhanced by the CDW effect, is the key mechanism responsible for the formation of the flat band in 1T-TaS₂ [4]. Third, through first-principles electric-field gradient calculations, we successfully reproduce the ³³S nuclear magnetic resonance (NMR) spectrum, revealing two critical interfacial structures in bulk 1T-TaS₂. This result establishes NMR combined with first-principles calculations as an effective method for analyzing complex stacking structures in layered materials [5]. Together, these DFT-based investigations provide a coherent picture of how electronic, lattice, and structural degrees of freedom cooperatively shape the emergent correlated states in 1T-TaS₂.

【参考文献】：

[1] Adv. Phys. 24, 117-201 (1975)  

[2] J. Phys. Condens. Matter 23, 213001 (2011)

[3] Phys. Rev. Res. 2, 023064 (2020)

[4] Phys. Rev. B 104, L241114 (2021)

[5] Phys. Rev. Mater. 7, L091001 (2023)

【报告人简介】：程丽，2025年于清华大学获得材料科学与工程博士学位，其学位论文荣获校级优秀论文。先后于2017年、2020年从烟台大学车辆工程专业、大连理工大学光学专业获得学士与硕士学位，随后在清华大学高等研究院访问一年。主要研究低维材料中电子关联现象，擅长结合实验现象给出理论解释。目前已发表SCI论文6篇，其中发表于Phys. Rev. B和Phys. Rev. Matter.的论文获得Physics专题报道及编辑推荐。