Mott physics in the half-filled Hubbard model on a family of vortex-full square lattices
Ixert D, Assaad FF, Schmidt KP (2014)
Publication Status: Published
Publication Type: Journal article
Publication year: 2014
Journal
Publisher: AMER PHYSICAL SOC
Book Volume: 90
Journal Issue: 19
DOI: 10.1103/PhysRevB.90.195133
Abstract
We study the half-filled Hubbard model on a one-parameter family of vortex-full square lattices ranging from the isotropic case to weakly coupled Hubbard dimers. The ground-state phase diagram consists of four phases: A semimetal and a band insulator which are connected to the weak-coupling limit, and a magnetically ordered Neel phase and a valence bond solid (VBS) which are linked to the strong-coupling Mott limit. The phase diagram is obtained by quantum Monte Carlo (QMC) and continuous unitary transformations (CUTs). The CUT is performed in a two-step process: Nonperturbative graph-based CUTs are used in the Mott insulating phase to integrate out charge fluctuations. The resulting effective spin model is tackled by perturbative CUTs about the isolated dimer limit yielding the breakdown of the VBS by triplon condensation. We find three scenarios when varying the interaction for a fixed anisotropy of hopping amplitudes: (i) one direct phase transition from Neel to semimetal, (ii) two phase transitions VBS to Neel and Neel to semimetal, or (iii) a smooth crossover from VBS to the band insulator. Our results are consistent with the absence of spin-liquid phases in the whole phase diagram.
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APA:
Ixert, D., Assaad, F.F., & Schmidt, K.P. (2014). Mott physics in the half-filled Hubbard model on a family of vortex-full square lattices. Physical Review B, 90(19). https://doi.org/10.1103/PhysRevB.90.195133
MLA:
Ixert, D., F. F. Assaad, and Kai Phillip Schmidt. "Mott physics in the half-filled Hubbard model on a family of vortex-full square lattices." Physical Review B 90.19 (2014).
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