Title: Topological Dirac and flat-band models and materials: The latest developments

Lecturer: Prof. Liu Feng
Date: 9:30-11:30, October 3, 2022
PLace: Tecent Meeting 182-929-805

Abstract: In this talk, I will discuss some recent progress in furthering our fundamental understanding of the physical underpinnings of topological materials in 2D lattice models, based on a unified correspondence principle between a “collective lattice coupling (CLC)” of two quantum states of quasiparticles and band topology. A zero CLC at special high-symmetry k-points corresponds to a Dirac semimetal, and a negative (positive) CLC at these k-points corresponds to a topological (normal) insulator; while a zero CLC at all k-points corresponds to a topological flat band. I will then discuss material realization of flat bands incorporating both orbital and lattice symmetries, such as in organic frameworks of metalorganic, covalent organic and H-bond organic frameworks, as well as inorganic 2D materials. Finally, I will discuss some recent studies of many-body quantum states arising from single and dual yin-yang flat bands, including fractional quantum Hall effect and excitonic Bose-Einstein condensation.

Resume: Feng Liu, Distinguished and Ivan B. Cutler Professor of Department of Materials Science and Engineering, University of Utah. He received his PhD in Chemical Physics from Virginia Commonwealth University in 1990. Prof. Liu is a fellow of American Physical Society and recipient of Senior Humboldt Award. His research interest lies in theoretical and computational studies of low-dimensional nano and quantum materials, with a most recent focus on topological and flat-band materials. He is also co-founder of two start-up companies.