Doping and temperature evolution of pseudogap and spin-spin correlations in the two-dimensional Hubbard model

Abstract

Cluster perturbation theory is applied to the two-dimensional Hubbard t − t ′ − t ′′ − U model to obtain doping and temperature dependent electronic spectral function with 4×4 and 12-site clusters. It is shown that evolution of the pseudogap and electronic dispersion with doping and temperature is similar and in both cases it is significantly influenced by spin-spin short-range correlations. When short-range magnetic order is weakened by doping or temperature and Hubbard-I like electronic dispersion becomes more pronounced, the Fermi arc turns into large Fermi surface and the pseudogap closes. It is demonstrated how static spin correlations impact the overall dispersion's shape and how accounting for dynamic contributions leads to momentum-dependent spectral weight at the Fermi surface and broadening effects.

Polaron transformations in the realistic model of the strongly correlated electron system

“…More detailed analysis is planned in future work. Note that the similar effect has been recently observed for the temperature and doping evolution of the band structure in the Hubbard model [58,59]. When the chemical potential enters into the flat band and the quantum phase transition is observed, the density of states raises sharply [Fig.…”

“…3(f) and 3(g)], and in the second, arcs are blurred and elongated to the boundaries of the Brillouin zone [Fig.4(b)]. In accordance with Ref [59],. we refer these states to the strong or weak pseudogap limit, respectively.…”

Determinantal Quantum Monte Carlo solver for Cluster Perturbation Theory

“…After introducing the formalism and implementation of the CPT+DQMC method, we will explore three examples: the attractive Hubbard model in a superconducting state, the half-filled repulsive Hubbard model, and the doped repulsive Hubbard model. In these examples, we will illustrate the advantages of the DQMC solver over the standard ED solver for CPT [13,14,[16][17][18][19][20][21][22][23][24][25][26][27], and also demonstrate the advantages of the CPT+DQMC method over finite size DQMC simulations. We conclude with a brief discussion of interesting open problems that are particularly suitable for study by CPT+DQMC.…”

Strong-coupling mechanism of the pseudogap in small Hubbard clusters

“…Calculations of the 2D Hubbard model have found a pseudogap in the single-particle spectra, with properties closely resembling those of photoemission and tunneling spectra of cuprates . These include its extent in the temperature-doping phase diagram [3,6,18,22,23,32] and the contrasting behaviors in the anti-nodal and nodal regions of the Brillouin zone, leading to the phenomena of Fermi arcs [12,14,15,20,21,25,31,32]. Apart from single-particle properties, other important aspects of pseudogap phenomenology in cuprate have been found and studied in the Hubbard model, including suppression of the spin susceptibility [6,28,[33][34][35][36] and presence of spin and charge density waves [37][38][39].…”

“…First, most of these calculations involve solving a small cluster that is part of the infinite system, via a generalization of dynamical mean-field theory or by cluster perturbation theory (CPT). Some of these, such as the CPT calculations in [10,25,27,32], do not permit long-range order, implying that short-range correlations are sufficient for generating the pseudogap. Viewed as simulations of the Hubbard model, such calculations are incorrect in the sense that they do not produce low-temperature ordered phases.…”