Regensburg 2022 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 11: Topology: Quantum Hall Systems
TT 11.4: Vortrag
Dienstag, 6. September 2022, 10:15–10:30, H10
antiferromagnetic chern insulator in a centrosymmetric system — •morad ebrahimkhas1, mohsen hafez-torbati2, and walter hofstetter1 — 1Institut für Theoretische Physik, Goethe-Universität, 60438 Frankfurt/Main, Germany — 2Lehrstuhl für Theoretische Physik I, Technische Universität Dortmund, Otto-Hahn-Straße 4, 44221 Dortmund, Germany
An antiferromagnetic Chern insulator (AFCI) can exist if the effect of the time-reversal transformation on the AF state cannot be compensated by a space group operation. Such a state has recently been reported in a noncentrosymmetric Kane-Mele-Hubbard model. We investigate the possible emergence of this phase in a centrosymmetric system. We consider a minimal extension of the time-reversal invariant Harper-Hofstadter- Hatsugai model. The next-nearest-neighbor hopping opens a gap at half-filling and allows for the realization of a quantum spin Hall insulator. We add to the system a staggered potential Δ and the Hubbard interaction U favoring a normal insulator and a Mott insulator, respectively. We map out the phase diagram of the model in the U-Δ plane and show that an AFCI with the Chern number C = 1 appears for (U∼2Δ) ≫ t. We find that for a fixed Δ upon increasing U a spin-flop transition from the C = 1 z-AFCI to a topologically trivial xy-AF phase takes place. Our findings can be used as a guideline in future investigations searching for an AFCI in optical lattices.