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arXiv · 1002.2304

Collinear antiferromagnetic state in a two-dimensional Hubbard model at half filling

Zeng-Qiang Yu·Lan Yin
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Abstract

In a half-filled Hubbard model on a square lattice, the next-nearest-neighbor hopping causes spin frustration, and the collinear antiferromagnetic (CAF) state appears as the ground state with suitable parameters. We find that there is a metal-insulator transition in the CAF state at a critical on-site repulsion. When the repulsion is small, the CAF state is metallic, and a van Hove singularity can be close to the Fermi surface, resulting in either a kink or a discontinuity in the magnetic moment. When the on-site repulsion is large, the CAF state is a Mott insulator. A first-order transition from the CAF phase to the antiferromagnetic phase and a second-order phase transition from the CAF phase to the paramagnetic phase are obtained in the phase diagram at zero temperature.

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Zeng-Qiang Yu, Lan Yin. 2010-02-11. Collinear antiferromagnetic state in a two-dimensional Hubbard model at half filling. https://doi.org/10.1103/physrevb.81.195122

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