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

AIP conference proceedings

Thermodynamic properties of the t-J-U model in the context of high-Tc cuprates

Chumki Tarafdar, Krishanu Roy, Nanda Kumar Ghosh

Published Jan 1, 2021• 1 citation
Publisher

Abstract

Some thermodynamic properties of the high-Tc cuprates have been studied using t-J-U model at different doping (<h>) by an exact method on a tilted square cluster. Low temperature specific heat curves show single-peak structure where the peak-height decreases with increasing <h>. The system becomes more disordered with decreasing hole occupancy. The extrapolation of all reciprocal susceptibility (χ-1) curves intercept at a negative temperature ΘN which suggests an antiferromagnetic correlation in the system.

DOI
10.1063/5.0061758

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 proceedings•Jan 1, 2017•3 citations

Thermodynamic Properties of the Planar t − J Model

Janez Jaklič, Peter Prelovšek

Several thermodynamic quantities within the planar $t\ensuremath{-}J$ model are calculated using the $T>0$ Lanczos method on clusters of up to 26 sites. The hole density ${c}_{h}(\ensuremath{\mu},T)$ shows a non-Fermi-liquid behavior as a function of $T$ and suggests a transition from small to large Fermi surfaces at ${c}_{h}\ensuremath{\sim}0.15$. The specific heat reveals a maximum at the exchange energy scale up to ${c}_{h}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.2$, where it becomes almost $T$ independent for $T\ensuremath{\gtrsim}0.15t$. At constant $T$ the entropy has maximum for ${c}_{h}\ensuremath{\sim}0.15$ with large values at low $T$, consistent with experiments on cuprates. In the underdoped regime the spin susceptibility ${\ensuremath{\chi}}_{0}(T)$ exhibits a maximum at finite ${T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}T}^{*}$, with ${T}^{*}$ decreasing with doping and disappearing for ${c}_{h}>0.15$.

arXiv:cond-mat/9603081•Physical Review Letters•Jul 29, 1996•66 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 proceedings•Jan 1, 2020•0 citations

Theory of Antiferromagnetic Correlations in High-Tc Cuprates

Masatoshi Imada

A phenomenological theory of the antiferromagnetic correlations in cuprates is constructed from analyses of recent numerical results of the Hubbard model. Two crossover temperatures are predicted to exist. In three regions divided by the two crossover temperatures, we present a qualitative but explicit form of doping and temperature dependences of the dynamical susceptibility χ( q , ω), which agrees with NMR and neutron scattering data of cuprates. It solves recent controversy between these two experimental results and provides us with a unified picture of antiferromagnetic correlation in cuprates.

Journal of the Physical Society of Japan•Mar 15, 1994•17 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 proceedings•Jan 1, 2020•1 citation

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 proceedings•Jan 1, 2021•0 citations
Some thermodynamic properties of the high-Tc cuprates have been studied using t-J-U model at different doping (<h>) by an exact method on a tilted square cluster. Low temperature specific heat curves show single-peak structure where the peak-height decreases with increasing <h>. The system becomes more disordered with decreasing hole occupancy. The extrapolation of all reciprocal susceptibility (χ-1) curves intercept at a negative temperature ΘN which suggests an antiferromagnetic correlation in the system.
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.
Several thermodynamic quantities within the planar $t\ensuremath{-}J$ model are calculated using the T>0T>0T>0 Lanczos method on clusters of up to 26 sites. The hole density ${c}_{h}(\ensuremath{\mu},T)$ shows a non-Fermi-liquid behavior as a function of TTT and suggests a transition from small to large Fermi surfaces at ${c}_{h}\ensuremath{\sim}0.15$. The specific heat reveals a maximum at the exchange energy scale up to ch=0.2{c}_{h}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.2ch​=0.2, where it becomes almost TTT independent for $T\ensuremath{\gtrsim}0.15t$. At constant TTT the entropy has maximum for ${c}_{h}\ensuremath{\sim}0.15$ with large values at low TTT, consistent with experiments on cuprates. In the underdoped regime the spin susceptibility ${\ensuremath{\chi}}_{0}(T)$ exhibits a maximum at finite T=T∗{T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}T}^{*}T=T∗, with T∗{T}^{*}T∗ decreasing with doping and disappearing for ch>0.15{c}_{h}>0.15ch​>0.15.
A phenomenological theory of the antiferromagnetic correlations in cuprates is constructed from analyses of recent numerical results of the Hubbard model. Two crossover temperatures are predicted to exist. In three regions divided by the two crossover temperatures, we present a qualitative but explicit form of doping and temperature dependences of the dynamical susceptibility χ( q , ω), which agrees with NMR and neutron scattering data of cuprates. It solves recent controversy between these two experimental results and provides us with a unified picture of antiferromagnetic correlation in cuprates.
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.
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.