AIP conference proceedings

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

Srijani Ghosh, Krishanu Roy, Nanda Kumar Ghosh

Published Jan 1, 2020• 0 citations

Abstract

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.

DOI: 10.1063/5.0002332

Related papers

High-Tc superconductivity: The t-J-V model and its applications

K. Roy, Papiya Pal, Subhadip Nath +1 more

We present numerical results of the t-J-V model in an 8-site tilted square cluster using exact diagonalization (ED) method with periodic boundary conditions. Effective hopping amplitude initially increases with inter-site Coulomb repulsion (V), but decreases at larger V’s. The hole-hole correlation decreases with inter-site distances at smaller V. With the increase of Coulomb repulsion, the system becomes ordered. The specific heat curves confirm the non-Fermi liquid behavior of the system under t-J-V model.

AIP conference proceedingsJan 1, 20173 citations

Some ground state characteristics of the high-Tc cuprates within t-J-U model

Chumki Tarafdar, Krishanu Roy, Nanda Kumar Ghosh

Exact diagonalization study based on Lanczos method has been performed to understand the effect of on-site Coulomb repulsion (U) within t-J-U model in an 8 – site tilted square cluster at a hole doping <h>= 0.25. We have applied periodic boundary conditions to identify complete orthonormal basis states. It appears that U destabilizes superconducting ground state. On-site Coulomb repulsion decreases kinetic energy of the electrons and cooperates with exchange interaction J.

AIP conference proceedingsJan 1, 20200 citations

Role of on-site hole-phonon interaction of high-Tc superconductivity within Holstein t-J model

Krishanu Roy, Chumki Tarafdar, Nanda Kumar Ghosh

Effect of on-site hole-phonon (h-ph) interaction within Holstein t-J model has been examined numerically using exact diagonalization (ED) technique within an 8 – site tilted square cluster at a hole doping <h>=0.25. We have applied periodic boundary conditions to obtain the basis states. It appears that with the increase of on-site h-ph interaction λ1 as well as phonon energy ω0, the ground state energy of the system reduces. Also, the enhancement of the number of phonons results in a significant decrease in ground state energy. At higher temperature, entropy decreases with λ1 as a result of the formation of S0 bipolarons. Low temperature specific heat indicates non-Fermi liquid behavior of the system.

AIP conference proceedingsJan 1, 20201 citation

On some ground state characteristics of the t-J-V model

Papiya Pal, K. Roy, Subhadip Nath +1 more

We present numerical results of the t – J – V model using exact diagonalization (ED) technique within an 8 – site tilted square cluster. Applying periodic boundary conditions, the calculations have been extended beyond the 8 – site limit. Inter-site Coulomb repulsion shifts the region of the formation of bound states. It softens the attractive exchange interaction decreasing d-wave pairing susceptibility. Short range antiferromagnetic (AF) order is present in the system for V/t ≤ 0.8.

AIP conference proceedingsJan 1, 20180 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

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