Influence of correlations on the orbital magnetization of the spin- 12 Haldane-Hubbard model

T. J. Sjöstrand, K. Karlsson, F. Aryasetiawan

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Abstract

Orbital magnetization is known empirically to play an important role in several magnetic phenomena, such as permanent magnetism and ferromagnetic superconductivity. Within the recently developed "modern theory of orbital magnetization," theoretical insight has been gained into the nature of this often neglected contribution to magnetism but is based on an underlying mean-field approximation. From this theory, a few treatments have emerged which also take into account correlations beyond the mean-field approximation. Here, we apply the scheme developed in a previous work [F. Aryasetiawan, Phys. Rev. B 93, 161104(R) (2016)2469-995010.1103/PhysRevB.93.161104] to the spin-12 Haldane-Hubbard model to investigate the effect of charge fluctuations on the orbital magnetization within the GW approximation. Qualitatively, we are led to distinguish between two quite different situations: (i) When the lattice potential is larger than the nearest-neighbor hopping, the correlations are found to boost the orbital magnetization. (ii) If the nearest-neighbor hopping is instead larger than the lattice potential, the correlations reduce the magnetization. The boost and reduction are identified to stem from interband and intraband correlations, respectively, and the relative importance of the two varies with the strength of the lattice potential. We finally study graphene with parameters obtained from first principles.

Original languageEnglish
Article number054427
JournalPhysical Review B
Volume100
Issue number5
DOIs
Publication statusPublished - 2019

Subject classification (UKÄ)

  • Condensed Matter Physics

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