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arXiv · 1804.00917

Phase diagram of the Hubbard-Kondo lattice model from variational cluster approximation

J. P. L. Faye·M. N. Kiselev·P. Ram·B. Kumar·D. Sénéchal
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Abstract

The interplay between the Kondo effect and magnetic ordering driven by the Ruderman-Kittel-Kasuya-Yosida interaction is studied within the two-dimensional Hubbard-Kondo lattice model. In addition to the antiferromagnetic exchange interaction, $J_\perp$, between the localized and the conduction electrons, this model also contains the local repulsion, $U$, between the conduction electrons. We use variational cluster approximation to investigate the competition between the antiferromagnetic phase, the Kondo singlet phase, and a ferrimagnetic phase on square lattice. At half-filling, the N\'eel antiferromagnetic phase dominates from small to moderate $J_\perp$ and $UJ_\perp$, and the Kondo singlet elsewhere. Sufficiently away from half-filling, the antiferromagnetic phase first gives way to a ferrimagnetic phase (in which the localized spins order ferromagnetically, and the conduction electrons do likewise, but the two mutually align antiferromagnetically), and then to the Kondo singlet phase.

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J. P. L. Faye, M. N. Kiselev, P. Ram, B. Kumar, D. Sénéchal. 2018-04-03. Phase diagram of the Hubbard-Kondo lattice model from variational cluster approximation. https://doi.org/10.1103/physrevb.97.235151

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