To investigate the non-Fermi liquid behavior we consider the extended two-dimensional t-J model which includes additional hopping t''. In the regime t,J << t'' we were able to solve the model analytically. It has a very rich phase diagram including antiferromagnetic (AF) insulator and AF strange metal with different kinds of pseudospin-singlet superconducting pairings (p,d,g-waves). We also demonstrate a collective triplet excitation with energy below the superconducting gapTo investigate the non-Fermi liquid behavior we consider the extended two-dimensional t-J model which includes additional hopping t''. In the regime t,J << t'' we were able to solve the model analytically. It has a very rich phase diagram including antiferromagnetic (AF) insulator and AF strange metal with different kinds of pseudospin-singlet superconducting pairings (p,d,g-waves). We also demonstrate a collective triplet excitation with energy below the superconducting gap

arXiv:cond-mat/9903028Mar 2, 19990 citations

The Ground and Low Lying Excited States of the Two-Dimensional Hubbard Model

Yoshihiro Asai

We have studied the ground state of the two-dimensional (2D) Hubbard model by using a quantum monte method paying special attention to the shell structure effect on finite size clusters. Our calculations show there is a gap for spin excitations in the ground state and incommensurate peaks at $(π\pm δ, π)$ and $(π, π\pm δ)$ in the spin correlation function for a low lying excited state. In the ground state, the long range part of the d-wave superconducting correlation function is enhanced and the momentum distribution function at the Fermi level $(π,0)$ is rounded. The gap in spin excitations and the momentum distribution function rounding is consistent with opening a d-wave superconducting gap in the ground state.We have studied the ground state of the two-dimensional (2D) Hubbard model by using a quantum monte method paying special attention to the shell structure effect on finite size clusters. Our calculations show there is a gap for spin excitations in the ground state and incommensurate peaks at $(π\pm δ, π)$ and $(π, π\pm δ)$ in the spin correlation function for a low lying excited state. In the ground state, the long range part of the d-wave superconducting correlation function is enhanced and the momentum distribution function at the Fermi level $(π,0)$ is rounded. The gap in spin excitations and the momentum distribution function rounding is consistent with opening a d-wave superconducting gap in the ground state.

arXiv:cond-mat/9904310Apr 22, 19990 citations

Symmetry of the superconducting phases in a two-dimensional t - J model

Jerzy Konior, Andrzej M. Oleś

Physica C SuperconductivityDec 1, 19913 citations

Superconductivity in the two-dimensionalt-J model at low electron density

M. Yu. Kagan, Thomas Maurice Rice

Czechoslovak Journal of PhysicsFeb 1, 19960 citations

Photoinduced superconducting states in strongly correlated electron systems

Akira Takahashi, Hiroki Gomi, Masaki Aihara

We theoretically investigate the properties of multiphoton excited states in strongly correlated two-dimensional electron systems. The effective Hamiltonian of the Hubbard model for the multiphoton excited states is derived assuming strong Coulomb repulsion. Diagonalizing the effective Hamiltonian exactly, the lowest energy state in two-photon excited manifold is calculated in the 20 site two-dimensional square lattice at half filling. Analysis of correlation functions suggests that the antiferromagnetic spin order characteristic of the half filled ground state is destroyed by two-photon excitation, and two different d-wave superconducting states and a spiral spin state are photogenerated.We theoretically investigate the properties of multiphoton excited states in strongly correlated two-dimensional electron systems. The effective Hamiltonian of the Hubbard model for the multiphoton excited states is derived assuming strong Coulomb repulsion. Diagonalizing the effective Hamiltonian exactly, the lowest energy state in two-photon excited manifold is calculated in the 20 site two-dimensional square lattice at half filling. Analysis of correlation functions suggests that the antiferromagnetic spin order characteristic of the half filled ground state is destroyed by two-photon excitation, and two different d-wave superconducting states and a spiral spin state are photogenerated.

Physical review. B, Condensed matterSep 3, 200215 citations

(π\pm δ, π)

and

(π, π\pm δ)

in the spin correlation function for a low lying excited state. In the ground state, the long range part of the d-wave superconducting correlation function is enhanced and the momentum distribution function at the Fermi level

(π,0)

is rounded. The gap in spin excitations and the momentum distribution function rounding is consistent with opening a d-wave superconducting gap in the ground state.