Interacting Weyl fermions: isolated Green’s function zeros, topology, and non-Fermi-liquid behaviour
Chris Hooley (Coventry University)
In this talk, I shall present some work carried out with Rafael Flores Calderón [1] in which we ask what happens if we take a model of fermions whose non-interacting dispersion relation contains a Weyl point and add a particular ‘toy-model’ type of electron-electron interaction (the Hatsugai-Kohmoto interaction). As I shall show, this separates the single-particle dispersion curves into upper and lower Hubbard bands with an energy gap between them, but leaves a zero of the single-particle Green’s function where the Weyl point used to be: we call this a “Weyl-Mott point.” Because of it, the insulating state obtained at intermediate values of the chemical potential is topological, and the boundary between the insulating and metallic states is a non-Fermi liquid.
[1] R. Flores-Calderón and CAH, “Weyl-Mott point: Topological and non-Fermi liquid behavior from an isolated Green’s function zero,” Phys. Rev. B 111, 235139 (2025).