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TT: Fachverband Tiefe Temperaturen
TT 65: Correlated Electrons: Other Theoretical Topics
TT 65.1: Talk
Friday, March 31, 2023, 09:30–09:45, HSZ 204
Quantum oscillations beyond the Onsager relation in a doped Mott insulator — •Valentin Leeb1,2 and Johannes Knolle1,2,3 — 1Technical University of Munich, Germany; TUM School of Natural Sciences, Department of Physics, TQM — 2Munich Center for Quantum Science and Technology (MCQST), 80799 Munich, Germany — 3Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
The kinetic energy of electrons in a magnetic field is quenched resulting in a discrete set of highly degenerate Landau levels (LL). This gives rise to fascinating phenomena like quantum oscillations or the integer and fractional quantum Hall effect. The latter is a result of interactions partially lifting the degeneracy within a given LL while inter-LL interactions are usually assumed to be unimportant. Here, we study the LL spectrum of the Hatsugai–Kohmoto model, a Hubbard-like model which is exactly soluble on account of infinite range interactions. For the doped Mott insulator phase in a magnetic field we find that the degeneracy of LLs is preserved but inter-LL interactions are important leading to a non-monotonous reconstruction of the spectrum. As a result, strong interactions lead to aperiodic quantum oscillations of the metallic phase in contrast to Onsager’s famous relation connecting oscillation frequencies with the Fermi surface areas at zero field. In addition, we find unconventional temperature dependencies of quantum oscillations and effective mass renormalizations. We discuss the general importance of inter-LL interactions for understanding doped Mott insulators in magnetic fields.