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arXiv · 1506.00501

Topological phases of the Kitaev-Hubbard Model at half-filling

J. P. L. Faye·S. R. Hassan·D. Sénéchal
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Abstract

The Kitaev-Hubbard model of interacting fermions is defined on the honeycomb lattice and, at strong coupling, interpolates between the Heisenberg model and the Kitaev model. It is basically a Hubbard model with ordinary hopping $t$ and spin-dependent hopping $t'$. We study this model in the weak to intermediate coupling regime, at half-filling, using the Cellular Dynamical Impurity Approximation (CDIA), an approach related to Dynamical Mean Field Theory but based on Potthoff's variational principle. We identify four phases in the $(U,t')$ plane: two semi-metallic phases with different numbers of Dirac points, an antiferromagnetic insulator, and an algebraic spin liquid. The last two are separated by a first-order transition. These four phases all meet at a single point and could be realized in cold atom systems.

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J. P. L. Faye, S. R. Hassan, D. Sénéchal. 2015-06-01. Topological phases of the Kitaev-Hubbard Model at half-filling. https://doi.org/10.1103/physrevb.89.115130

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