Finite compressibility in the low-doping region of the two-dimensional $t-J$ model

Abstract

We revisit the important issue of charge fluctuations in the two-dimensional $t-J$ model by using an improved variational method based on a wave function that contains both the antiferromagnetic and the d-wave superconducting order parameters. In particular, we generalize the wave function introduced some time ago by J.P. Bouchaud, A. Georges, and C. Lhuillier [J. de Physique {\bf 49}, 553 (1988)] by considering also a {\it long-range} spin-spin Jastrow factor, in order to correctly reproduce the small-$q$ behavior of the spin fluctuations. We mainly focus our attention on the physically relevant region $J/t\sim 0.4$ and find that, contrary to previous variational ansatz, this state is stable against phase separation for small hole doping. Moreover, by performing projection Monte Carlo methods based on the so-called fixed-node approach, we obtain a clear evidence that the $t-J$ model does not phase separate for $J/t\lesssim 0.7$ and that the compressibility remains finite close to the antiferromagnetic insulating state.

10 pages

References in corpus (2)

• Magnetism and superconductivity of strongly correlated electrons on the triangular lattice
• Slave-boson approach to the metallic stripe phases with large unit cells

Cited by in corpus (9)

• Absence of superconductivity in the pure two-dimensional Hubbard model
• Crossover between BCS Superconductor and Doped Mott Insulator of d-wave Pairing State in Two-Dimensional Hubbard Model
• Simulation of fermionic lattice models in two dimensions with Projected Entangled-Pair States: Next-nearest neighbor Hamiltonians
• Magnetism and superconductivity in the $t-t^{\prime }-J$ model
• Hidden Mott transition and large-$U$ superconductivity in the two-dimensional Hubbard model
• Fidelity and superconductivity in two-dimensional t-J models
• Effective approach to the Nagaoka regime of the two dimensional t-J model
• Projected d-wave superconducting state: a fermionic projected entangled pair state study
• Ising t-J model close to half filling: A Monte Carlo study