Jun 20 – 23, 2022
Max Planck Institut für Festkörperforschung
Europe/Berlin timezone

Hund, phonons, Hubbard U: Friends or foes?

Jun 21, 2022, 10:45 AM
2D5 (Max Planck Institut für Festkörperforschung)


Max Planck Institut für Festkörperforschung

Keynote Talk / Invited Talk Frustration and Quantum Magnetism


Massimo Capone (International School for Advanced Studies (SISSA))


I will present some results showing that the Hubbard repulsion and other interactions like the Hund's coupling and electron-phonon interaction can either compete or cooperate, leading to different strongly correlated phases.

First I will review the interplay between Hubbard U and Hund's coupling emphasizing how different fillings are characterized by different scenarios. Namely at half-filling the two interactions cooperate to localize the electrons in a high-spin Mott state, while for other integer fillings they compete, leading to a Hund's metal region bridging two strongly correlated insulators [1].

I will then address how an electron-phonon coupling changes the picture. In a two-orbital model we witness a cooperation between the Hubbard U and Jahn-Teller phonons, while the latter compete with the Hund's coupling. Also in this case we deal with the competition between two Mott insulators bridged by a hybrid insulator with mixed properties [2]

[1]A. Isidori, M Berovic, L. Fanfarillo, L. de' Medici, M. Fabrizio and M. Capone, Phys. Rev. Lett. 122, 186401 (2019)
[2] A. Scazzola, A. Amaricci and M. Capone, arXiv:2111.14663

Primary author

Massimo Capone (International School for Advanced Studies (SISSA))

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