AIP conference proceedings

Hole pairing and thermodynamic properties of the two dimensional frustrated t-J model

K. Roy, Papiya Pal, Subhadip Nath, Nanda Kumar Ghosh

Published Jan 1, 2018• 0 citations

Abstract

The frustrated t-J model is investigated by using the exact-diagonalization (ED) method on an 8-site cluster. The effect on next-nearest-neighbor (NNN) exchange interaction J′ (frustration) on the hole pairing and the thermodynamic properties of the system is considered. Two holes initially remain unbound at smaller value of J′/t, but tend to bind at larger value. The maximum possibility of pair formation has been observed to be at NNN sites. Entropy calculation shows that the system goes to more disordered state with J′. The specific heat curves show a single peak structure. A decrease in effective exchange energy is observed due to the frustration.

DOI: 10.1063/1.5029082

Related papers

Hole correlation and thermodynamic properties of the 2D t-t'-t''-J model

Krishanu Roy, Srijani Ghosh, Nanda Kumar Ghosh

The role of next nearest neighbor (NNN) hopping (t') and next to NNN hopping (t'') on hole pairing and thermodynamic properties such as specific heat, entropy have been investigated using two dimensional (2D) hole-doped t-t'-t''-J model based on exact diagonalization (ED) method. Standard Periodic boundary conditions are applied to minimize error due to finite size effect as the calculations are made using small sized cluster geometry. The attraction between holes increases with the inclusion of third neighbor hopping term. The maximum probability of hole pairing is at NNN site. The system goes to more disordered and ordered state with the increase of long range hopping terms at temperature T≤0.35t and T>0.35t, respectively. A single peak nature is observed in specific heat graph.

AIP conference proceedingsJan 1, 20210 citations

Hole and pair structures in the t-J model

Steven R. White, Douglas J. Scalapino

Using numerical results from density matrix renormalization group (DMRG) calculations for the t-J model, on systems as large as 10\ifmmode\times\else\texttimes\fi{}7, we examine the structure of the one and two hole ground states in ladder systems and in two dimensional clusters. A simple theoretical framework is used to explain why holes bind in pairs in two-dimensional antiferromagnets. For the case J/t=0.5, which we have studied, the hole pairs reside predominantly on a 2\ifmmode\times\else\texttimes\fi{}2 core plaquette with the probability that the holes are on diagonal sites greater than nearest-neighbor sites. There is a strong singlet bond connecting the spins on the two remaining sites of the plaquette. We find that a general characteristic of dynamic holes in an antiferromagnet is the presence of frustrating antiferromagnetic bonds connecting next-nearest-neighbor sites across the holes. Pairs of holes bind in order to share the frustrating bonds. At low doping, in addition to hole pairs, there are two additional low-energy structures which spontaneously form on certain finite systems. The first is an undoped L\ifmmode\times\else\texttimes\fi{}2 spin-liquid region, or ladder. The second is a hole moving along a one dimensional chain of sites. At higher doping we expect that hole pairing is always favored.

arXiv:cond-mat/9605143Physical review. B, Condensed matterMar 1, 1997165 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 proceedingsJan 1, 20130 citations

High-Tc superconductivity within t-J-V-Vʹ model

Srijani Ghosh, Krishanu Roy, Nanda Kumar Ghosh

We present numerical results on the role of next-nearest-neighbor (NNN) Coulomb repulsion within t-J-V-Vʹ model using exact diagonalization (ED) technique within an 8 – site tilted square cluster at a hole doping <h>=0.25. Periodic boundary conditions have been applied to obtain complete basis states. It appears that hole-hole correlation is dominant at d = √2. NNN Coulomb repulsion localizes the electrons and cooperates with exchange interaction J. Non-Fermi liquid behavior of the model has been confirmed.

AIP conference proceedingsJan 1, 20200 citations

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

José A. Riera

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.

Physical review. B, Condensed matterJul 1, 198924 citations

Signatures of next-nearest-neighbor (NNN) Antiferromagnetic Exchange Interaction on High-Tc Superconductivity Within t-t'-J-J' Model

K Roy, Papiya Pal, Nanda Kumar Ghosh

The influence of the next-nearest-neighbor (NNN) antiferromagnetic interaction J ’has been examined within t-t'-J-J ’model in an exact technique. An 8-site square cluster is chosen as the representative of the system. The effect of the next-nearest-neighbor (NNN) antiferromagnetic interaction on various ground state properties such as electron-electron correlation, spin-spin correlation, effective hopping amplitude etc. has been studied. Temperature variation of the susceptibility shows that J ’suppresses short range antiferromagnetic order. Applying periodic boundary conditions, the calculations have been extended beyond the 8-site limit.

Bulletin of Pure & Applied Sciences- PhysicsJan 1, 20182 citations