Role of Frustration and Dimensionality in the Hubbard Model on the Stacked Square Lattice: Variational Cluster Approach

Toshihiko Yoshikawa; Masao Ogata

doi:10.1103/PhysRevB.79.144429

paper

Role of Frustration and Dimensionality in the Hubbard Model on the Stacked Square Lattice: Variational Cluster Approach

arXiv:0804.2548 · doi:10.1103/PhysRevB.79.144429

Abstract

Using variational cluster approach, we study influence of frustration and dimensionality on magnetic properties in the ground state of Hubbard model on a stacked square lattice in the large $U$ region (U/t=10), by changing the next-nearest-neighbor hopping, $t^{'}$ , and the interlayer hopping, $t_{⊥}$ . For small $t_{⊥} < t_{⊥}^{*}$ with $t_{⊥}^{*} / t \approx 0.44$ , antiferromagnetic long-range order appears at small $t^{'} < t_{c_{1}}^{'}$ , and collinear magnetic long-range order at large $t^{'} > t_{c_{2}}^{'}$ . They are separated by a paramagnetic Mott insulating state which appears in the parameter region $t_{c_{1}}^{'} < t^{'} < t_{c_{2}}^{'}$ . For large $t_{⊥} > t_{⊥}^{*}$ , the paramagnetic Mott insulating state disappears and a direct transition between antiferromagnetic state and collinear magnetic state occurs at $t^{'} = t_{c_{3}}^{'}$ . We also find that the transition from the antiferromagnetic state to the paramagnetic Mott insulating state is of the second-order and that from the collinear magnetic state to the paramagnetic Mott insulating or the antiferromagnetic state is of the first-order.

7 pages, 6 figures, submitted to Physical Review B

Role of Frustration and Dimensionality in the Hubbard Model on the Stacked Square Lattice: Variational Cluster Approach

Abstract

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