Gapless Topology and Electron Correlations
February 19, 2024 (Mon.) at 1:30PM (ET)
Rice University
Electrons in a crystal behave as waves that interfere with one another. Accordingly, an electronic system can have non-trivial properties when viewed through the lens of topology. At the same time, the electrons also exist as charged particles that repel one another, which raises the question of whether strong electrostatic interactions can cooperate with the wave nature of the electrons to produce correlated topological matter. For insulators, the answer is long known in affirmative as exemplified by the fractional quantum Hall effect. In the case of metallic systems, however, the question is largely open and pressing.
In this talk, I will outline the route we have taken from certain canonical correlation physics to correlated metallic topology. I’ll show how correlation effects in the form of Kondo interactions produce emergent excitations that are subjected to the constraints of crystalline symmetry, leading to Weyl-Kondo semimetals [1,2]. I will describe a design principle for new materials that realize a variety of Weyl-Kondo semimetals, both for heavy fermion materials [3] and flat-band-hosting transition metal systems [4]. Finally, I will discuss the interplay between topology and strange metallicity, both in f-electron systems [5] and flat-band systems [6]. Some general about topology and correlation physics in general will be discussed.
[1] H.-H. Lai, S. E. Grefe, S. Paschen, and Q. Si, PNAS 115, 93 (2018).
[2] S. Dzsaber et al., PNAS 118, e2013386118 (2021).
[3] L. Chen et al, Nat. Phys. 18, 1341 (2022).
[4] H. Hu, Q. Si, Sci. Adv. 9, eadg0028 (2023); L. Chen et al., arXiv:2212.08017.
[5] L. Chen et al., unpublished (2024); H. Hu et al., arXiv:2110.06182.
[6] L. Chen et al, arXiv:2307.09431.