1207.6261 (Luca F. Tocchio et al.)

Mott correlated states in the underdoped two-dimensional Hubbard model:
variational Monte Carlo versus a dynamical cluster approximation    [PDF]

Luca F. Tocchio, Hunpyo Lee, Harald O. Jeschke, Roser Valenti, Claudius Gros

We investigate the properties of the frustrated underdoped Hubbard model on the square lattice using two complementary approaches, the dynamical cluster extension of dynamical mean field theory, and variational Monte Carlo simulations of Gutzwiller-Jastrow wavefunctions with backflow corrections. We find good agreement, apart from the location of the Mott-Hubbard transition which differs. At small dopings, we observe a rapid crossover from a weakly correlated metal at low interaction strength $U$ to a non Fermi liquid correlated state with strong local spin correlations, which we identify as the pseudo-gap state of the high-$T_c$ superconductors. Furthermore, we investigate the stability of the pseudo-gap state against phase separation. We observe phase separation only for large values of $U$ or very large frustration. No phase separation is present for the parameter range relevant for the cuprates.

View original: http://arxiv.org/abs/1207.6261