A flat band-induced correlated kagome metal

Van Hove Charge Density Waves on Hexagonal Lattices and Kagome Superconductors
September 30, 2022

Monday, October 24, 2022 from 2:30-3:30 p.m.
Location: 325 Physics South Hall & Zoom
Speaker: Linda Ye, Stanford University

Abstract: The notion of an electronic flat band refers to a collectively degenerate set of quantum mechanical eigenstates in periodic solids. The vanishing kinetic energy of flat bands relative to the electron-electron interaction is expected to result in a variety of many-body quantum phases of matter. Despite intense theoretical interest, systematic design and experimental realization of such flat band-driven correlated states in natural crystals have remained a challenge. Here we report the realization of a partially filled flat band in a new single crystalline kagome metal Ni3In [1]. This flat band is found to arise from the Ni-orbital wave functions localized at triangular motifs within the kagome lattice plane, where an underlying destructive interference among hopping paths flattens the dispersion. We observe unusual metallic and thermodynamic responses suggestive of the presence of local fluctuating magnetic moments originating from the flat band states, which together with non-Fermi liquid behavior indicate proximity to quantum criticality. These results demonstrate a lattice and orbital engineering approach to designing flat band-based many-body phenomena that may be applied to integrate correlation with topology and as a novel means to construct quantum criticality. If time allows, I will also discuss our application of the adiabatic elastocaloric effect [2] in studying anisotropic fluctuations and entropy landscapes of a number of f electron systems.


[1] L. Ye et al., arXiv/2106.10824
[2] M. Ikeda et al., Rev. Sci. Instrum. 90, 083902 (2019).

Bio: Linda Ye is currently a Marvin Chodorow postdoctoral fellow at the Department of Applied Physics at Stanford University and is going to join the Division of Physics, Mathematics and Astronomy as an Assistant Professor of Physics at California Institute of Technology from September 2023. Her research interests include designing, synthesizing and strain-tuning of topological and correlated quantum materials. She received her doctoral degree in Physics from Massachusetts Institute of Technology in 2020.

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