Kuang-Shing Chen, Zi Yang Meng, Thomas Pruschke, Juana Moreno, Mark Jarrell
Using large-scale dynamical cluster quantum Monte Carlo simulation, we study the Lifshitz transition of the two dimensional Hubbard model with next-nearest-neighbor hopping (t'), chemical potential and temperature as control parameters. At $t'\le0$, we identify a line of Lifshitz transition points associated with a change of the Fermi surface topology at zero temperature. In the overdoped region, the Fermi surface is complete and electron-like; across the Lifshitz transition, the Fermi surface becomes hole-like and develops a pseudogap. At (or very close to) the Lifshitz transition points, a van Hove singularity in the density of states crosses the Fermi level. The van Hove singularity occurs at finite doping due to correlation effects, and becomes more singular when t' becomes more negative. The resulting temperature dependence on quantities such as the bare d-wave pairing susceptibility close to the Lifshitz points is significantly different from that found in the traditional van Hove scenarios. Such unambiguous numerical observation of the Lifshitz transition at $t'\le0$ extends our understanding of quantum critical region of the phase diagram, and shines lights on future investigations of the nature of the quantum critical point in the two dimensional Hubbard model.
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http://arxiv.org/abs/1207.0796
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