Quantum Criticality and Incipient Phase Separation in the Thermodynamic Properties of the Hubbard Model

Abstract

Transport measurements on the cuprates suggest the presence of a quantum critical point hiding underneath the superconducting dome near optimal hole doping. We provide numerical evidence in support of this scenario via a dynamical cluster quantum Monte Carlo study of the extended two-dimensional Hubbard model. Single particle quantities, such as the spectral function, the quasiparticle weight and the entropy, display a crossover between two distinct ground states: a Fermi liquid at low filling and a non-Fermi liquid with a pseudogap at high filling. Both states are found to cross over to a marginal Fermi-liquid state at higher temperatures. For finite next-nearest-neighbor hopping t' we find a classical critical point at temperature T_c. This classical critical point is found to be associated with a phase separation transition between a compressible Mott gas and an incompressible Mott liquid corresponding to the Fermi liquid and the pseudogap state, respectively. Since the critical temperature T_c extrapolates to zero as t' vanishes, we conclude that a quantum critical point connects the Fermi-liquid to the pseudogap region, and that the marginal-Fermi-liquid behavior in its vicinity is the analogous of the supercritical region in the liquid-gas transition.

18 pages, 9 figures

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Cited by in corpus (10)

• Lifshitz Transition in the Two Dimensional Hubbard Model
• Bad-Metallic Behavior of Doped Mott Insulators
• Evolution of the Superconductivity Dome in the two dimensional Hubbard Model
• Charge-fluctuations in lightly hole-doped cuprates: effect of vertex corrections
• Phase separation in doped Mott insulators
• Mott Quantum Critical Points at finite doping
• Entropy in the non-Fermi-liquid regime of the doped $2d$ Hubbard model
• Metal-Mott insulator interfaces
• Spin correlations in the bilayer Hubbard model with perpendicular electric field
• Evaluating second-order phase transitions with Diagrammatic Monte Carlo: Néel Transition in the doped three-dimensional Hubbard model