Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical review. B, Condensed matter

Binding of holes in the Hubbard model with next-nearest-neighbor hopping

José A. Riera

Published Jul 1, 1989• 24 citations
Publisher

Abstract

We study the two-dimensional Hubbard model with next-nearest-neighbor hoppings and its related strong-coupling effective Hamiltonian by exact diagonalization. We found that the binding energy of holes tends to be smaller than with nearest neighbors only. However, the tendency towards phase separation is reduced by increasing the next-nearest-neighbor hopping. By studying pairing correlations, we found that the mode is strongly enhanced when the second-neighbor interactions are turned on.

DOI
10.1103/physrevb.40.833

Related papers

Hole motion in thet-Jand Hubbard models: Effect of a next-nearest-neighbor hopping

Eduardo R. Gagliano, Silvia Bacci, Elbio R. Dagotto

Using exact diagonalization techniques, we study one dynamical hole in the two-dimensional t-J and Hubbard models on a square lattice including a next-nearest-neighbor hopping t'. We present the phase diagram in the parameter space (J/t,t'/t), discussing the ground-state properties of the hole. At J=0, a crossing of levels exists at some value of t' separating a ferromagnetic from an antiferromagnetic ground state. For nonzero J, at least four different regions appear where the system behaves like an antiferromagnet or a (not fully saturated) ferromagnet. We study the quasiparticle behavior of the hole, showing that for small values of \ensuremath{\Vert}t'\ensuremath{\Vert} the previously presented string picture is still valid. We also find that, for a realistic set of parameters derived from the Cu-O Hamiltonian, the hole has momentum (\ensuremath{\pi}/2,\ensuremath{\pi}/2), suggesting an enhancement of the p-wave superconducting mode due to the second-neighbor interactions in the spin-bag picture. Results for the t-t'-U model are also discussed with conclusions similar to those of the t-t'-J model. In general we found that t'=0 is not a singular point of these models.

Physical review. B, Condensed matter•Oct 1, 1990•30 citations

Second-Neighbor Hopping Effects in the Two-Dimensional Attractive Hubbard Model

Rodrigo A. Fontenele, Nathan Vasconcelos, Natanael C. Costa +2 more

The emergence of superconductivity (SC) in lattice models, such as the attractive Hubbard one, has renewed interest since the realization of cold-atom experiments. However, reducing the temperature in these experiments is a bottleneck; therefore, investigating how to increase the energy scale for SC is crucial to cold atoms. In view of this, we examine the effects of next-nearest-neighbor hoppings (t′) on the pairing properties of the attractive Hubbard model in a square lattice. To this end, we analyze the model through unbiased Quantum Monte Carlo simulations for fixed density n=0.87, and perform finite-size scaling analysis to the thermodynamic limit. As our main result, we notice that the existence of further hopping channels leads to an enhancement of the pairing correlations, which, in turn, increases the ground-state order parameter Δ. Finally, at finite temperatures, for t′/t≠0, this enhancement of pairing correlations leads to an increase in the critical temperature Tc. That is, the fine-tuning of second-neighbor hoppings increases the energy scales for SC, and may be a route by which cold-atom experiments can achieve such a phase and to help us further understand the nature of this phenomenon.

Condensed Matter•Jan 17, 2023•2 citations

Optimal inhomogeneity for pairing in Hubbard systems with next-nearest-neighbor hopping

Gideon Wachtel, Shirit Baruch, Dror Orgad

Previous studies have shown that bipartite Hubbard systems with inhomogeneous hopping amplitudes can exhibit higher pair-binding energies than the uniform model. Here we examine whether this result holds for systems with a more generic band structure. To this end, we use exact diagonalization and the density matrix renormalization-group method to study the $4\ifmmode\times\else\texttimes\fi{}4$ Hubbard cluster and the two-leg Hubbard ladder with checkerboard-modulated nearest-neighbor hopping, $t$, and next-nearest-neighbor (diagonal) hopping, ${t}_{d}$. We find that the strongest pairing continues to occur at an intermediate level of inhomogeneity. While the maximal pair-binding energy is enhanced by a positive ${t}_{d}/t$, it is suppressed and appears at weaker repulsion strengths and lower hole concentrations when ${t}_{d}/t$ is negative. We point out a possible connection between the pairing maximum and the magnetic properties of the system.

arXiv:1706.05023•Physical review. B./Physical review. B•Aug 30, 2017•11 citations

Langevin Simulation of the Two-Dimensional Hubbard Model

Kazuo Saitoh, Satoshi Takada

The two-dimensional (2-D) Hubbard model with nearest-neighbor and next-nearest-neighbor (n.n.n.) hopping are studied using the Langevin method. Results of the staggered magnetic susceptibility and the pairing susceptibilities are shown. It is found that the effect of n.n.n. hopping destroys the antiferromagnetic correlation and assists the tendency of pairing. The possibility of superconductivity in the Hubbard model in the presence of n.n.n. hopping is discussed.

Journal of the Physical Society of Japan•Mar 15, 1989•6 citations

Ground state properties of the frustrated Hubbard model

Subhadip Nath, Nanda Kumar Ghosh, S. K. Bhowmick +1 more

The 2D Hubbard model extended by next-nearest-neighbor (NNN) hopping is considered at T→0. The dwave pairing susceptibility is enhanced with NNN hopping. In the interacting case (U≠0), the hole-hole correlation decreases with NNN hopping. The hole-hole correlation is dominant at NNN sites which decrease with increase of NNN hopping strength.

AIP conference proceedings•Jan 1, 2013•0 citations

Pairing in a tight-binding model with occupation-dependent hopping rate: Exact diagonalization study

H. Q. Lin, J. E. Hirsch

The Hubbard model with occupation-dependent hopping rate exhibits superconductivity in a wide range of parameters within mean-field (BCS) theory. Here we study pair binding energies in this model for small clusters by exact diagonalization of the Hamiltonian. The model is defined by on-site and nearest-neighbor repulsions U and V, and occupation-dependent hopping rate t(n)=t+n\ensuremath{\Delta}t. We present results for one-dimensional chains and for two-dimensional square lattices of sizes 4\ifmmode\times\else\texttimes\fi{}4, 6\ifmmode\times\else\texttimes\fi{}6, and 8\ifmmode\times\else\texttimes\fi{}8. As a function of carrier density n the pair binding energy first increases and then decreases, and vanishes beyond a critical density. BCS results for the pair binding energy are found to be in remarkably good agreement with the exact results. In particular, BCS theory accurately reproduces the range of interaction parameters where pair binding exists in the exact solution. The model is found to exhibit no tendency to phase separation or clustering of more than two particles even for parameters giving rise to strong pair binding, in contrast to other tight-binding models where pairing occurs.

Physical review. B, Condensed matter•Dec 1, 1995•20 citations
We study the two-dimensional Hubbard model with next-nearest-neighbor hoppings and its related strong-coupling effective Hamiltonian by exact diagonalization. We found that the binding energy of holes tends to be smaller than with nearest neighbors only. However, the tendency towards phase separation is reduced by increasing the next-nearest-neighbor hopping. By studying pairing correlations, we found that the mode is strongly enhanced when the second-neighbor interactions are turned on.
Using exact diagonalization techniques, we study one dynamical hole in the two-dimensional t-J and Hubbard models on a square lattice including a next-nearest-neighbor hopping t'. We present the phase diagram in the parameter space (J/t,t'/t), discussing the ground-state properties of the hole. At J=0, a crossing of levels exists at some value of t' separating a ferromagnetic from an antiferromagnetic ground state. For nonzero J, at least four different regions appear where the system behaves like an antiferromagnet or a (not fully saturated) ferromagnet. We study the quasiparticle behavior of the hole, showing that for small values of \ensuremath{\Vert}t'\ensuremath{\Vert} the previously presented string picture is still valid. We also find that, for a realistic set of parameters derived from the Cu-O Hamiltonian, the hole has momentum (\ensuremath{\pi}/2,\ensuremath{\pi}/2), suggesting an enhancement of the p-wave superconducting mode due to the second-neighbor interactions in the spin-bag picture. Results for the t-t'-U model are also discussed with conclusions similar to those of the t-t'-J model. In general we found that t'=0 is not a singular point of these models.
The emergence of superconductivity (SC) in lattice models, such as the attractive Hubbard one, has renewed interest since the realization of cold-atom experiments. However, reducing the temperature in these experiments is a bottleneck; therefore, investigating how to increase the energy scale for SC is crucial to cold atoms. In view of this, we examine the effects of next-nearest-neighbor hoppings (t′) on the pairing properties of the attractive Hubbard model in a square lattice. To this end, we analyze the model through unbiased Quantum Monte Carlo simulations for fixed density n=0.87, and perform finite-size scaling analysis to the thermodynamic limit. As our main result, we notice that the existence of further hopping channels leads to an enhancement of the pairing correlations, which, in turn, increases the ground-state order parameter Δ. Finally, at finite temperatures, for t′/t≠0, this enhancement of pairing correlations leads to an increase in the critical temperature Tc. That is, the fine-tuning of second-neighbor hoppings increases the energy scales for SC, and may be a route by which cold-atom experiments can achieve such a phase and to help us further understand the nature of this phenomenon.
Previous studies have shown that bipartite Hubbard systems with inhomogeneous hopping amplitudes can exhibit higher pair-binding energies than the uniform model. Here we examine whether this result holds for systems with a more generic band structure. To this end, we use exact diagonalization and the density matrix renormalization-group method to study the $4\ifmmode\times\else\texttimes\fi{}4$ Hubbard cluster and the two-leg Hubbard ladder with checkerboard-modulated nearest-neighbor hopping, ttt, and next-nearest-neighbor (diagonal) hopping, td{t}_{d}td​. We find that the strongest pairing continues to occur at an intermediate level of inhomogeneity. While the maximal pair-binding energy is enhanced by a positive td/t{t}_{d}/ttd​/t, it is suppressed and appears at weaker repulsion strengths and lower hole concentrations when td/t{t}_{d}/ttd​/t is negative. We point out a possible connection between the pairing maximum and the magnetic properties of the system.
The Hubbard model with occupation-dependent hopping rate exhibits superconductivity in a wide range of parameters within mean-field (BCS) theory. Here we study pair binding energies in this model for small clusters by exact diagonalization of the Hamiltonian. The model is defined by on-site and nearest-neighbor repulsions U and V, and occupation-dependent hopping rate t(n)=t+n\ensuremath{\Delta}t. We present results for one-dimensional chains and for two-dimensional square lattices of sizes 4\ifmmode\times\else\texttimes\fi{}4, 6\ifmmode\times\else\texttimes\fi{}6, and 8\ifmmode\times\else\texttimes\fi{}8. As a function of carrier density n the pair binding energy first increases and then decreases, and vanishes beyond a critical density. BCS results for the pair binding energy are found to be in remarkably good agreement with the exact results. In particular, BCS theory accurately reproduces the range of interaction parameters where pair binding exists in the exact solution. The model is found to exhibit no tendency to phase separation or clustering of more than two particles even for parameters giving rise to strong pair binding, in contrast to other tight-binding models where pairing occurs.