The Falicov-Kimball Model in External Magnetic Field: Orbital Effects |

M. Wróbel, M. Mierzejewski and M.M. Maśka
Department of Theoretical Physics, Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland |

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We study thermodynamic properties of the two-dimensional (2D) Falicov-Kimball model in the presence of external magnetic field perpendicular to the lattice. The field is taken into account by the Peierls substitution in the hopping term. We show how the Hofstadter butterfly is affected by electronic correlations. In the non-interacting case the field dependent energy spectrum forms the famous Hofstadter butterfly. Our results indicate that for arbitrary nonzero interaction strength and arbitrary magnetic field there is a gap in the energy spectrum at sufficiently low temperature. The gap vanishes with increase of temperature for weak coupling, however, it persists at high temperatures if the coupling is strong enough. Numerical results have been obtained with the help of Monte Carlo technique based on a modified Metropolis algorithm. |

DOI: 10.12693/APhysPolA.118.379 PACS numbers: |