Exact-diagonalization demonstration of incommensurability and the associated Fermi surface forNholes in thet-Jmodel

We present simple calculations which show that the incommensurability upon doping and the width of the magnetically ordered phase in Mott-Hubbard insulators depend strongly on the location of the hole/electron pockets in the Brillouin zone. For LaSrCuO systems, we found the pockets at (±π/2, ±π/2), in which case the corrections to the antiferromagnetic spin stiffness rapidly grow with doping and destroy commensurate spin ordering already at a very small doping. On the other hand, in N dCeCuO, the hole pockets are located at (π, 0) and the symmetry related points, in which case the corrections to the stiffness scale linearly with the density of carriers and do not destroy commensurate spin ordering. For Y BCO systems, the situation is less certain, but our results favor hole pockets at (π/2, π/2). We also briefly discuss the tendency towards phase separation.

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“…This agrees with the numerical [24,20,25] and variational [26] studies of the Hubbard and t − J models.…”

Section: B Finite Density Of Holessupporting

confidence: 88%

“…For |t ′ | > J, the minimum of the hole dispersion is at k = (π, π) (or (0, 0)). Finally, if t ′ is positive, which is probably not the case for cuprates, the minimum of E d is at (π, 0) and symmetry related points [20]. Now, for both 214 compounds, t ′ is negative and relatively small:…”

Section: B Finite Density Of Holesmentioning

confidence: 92%

On the contrasting spin dynamics of La_2-xSr_xCuO₄, Nd_2-xCe_xCuO₄and YBa₂Cu₃O_6+xnear half filling

Chubukov

Musaelian

1995

J. Phys.: Condens. Matter

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“…The result that the critical d h for negative t t ¢/ is smaller than that of t¢ = 0 case is consistent with the results evaluated by exact diagonalization [35,36] and the suppression of coexistence of AFLRO and SC is consistent with the slave-boson mean-field theory [37].…”

Section: ¢ = -supporting

confidence: 86%

Antiferromagnetism and superconductivity of the two-dimensional extended t-J model

Shih

Chen

et al. 2005

Low Temperature Physics

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“…However, the shift in k may be too small to be detected in our finite lattice with discrete k. In previous ED studies of the t-J model on smaller lattices, the shift in S(k) was not observed until the doping level is much larger. 25,26 On the other hand, experiments have demonstrated incommensurability in the magnetic fluctuation. 27 Therefore one should not look for long-range order that exists in the thermodynamic limit, but should instead look for short-range spiral order.…”

Section: Spin Correlationmentioning

confidence: 99%

Low-energy states with different symmetries in thet−Jmodel with two holes on a 32-site lattice

Leung

2002

Phys. Rev. B

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We study the low-energy states of the t-J model with two holes on a 32-site lattice with periodic boundary conditions. In contrary to common belief, we find that the state with d x 2 Ϫy 2 symmetry is not always the ground state in the realistic parameter range 0.2рJ/tр0.4. There exist low-lying finite-momentum p states whose energies are lower than the d x 2 Ϫy 2 state when J/t is small enough. We compare various properties of these low-energy states at J/tϭ0.3 where they are almost degenerate and find that those properties associated with the holes ͑such as the hole-hole correlation and the electron momentum distribution function͒ are very different between the d x 2 Ϫy 2 and p states, while their spin properties are very similar. Finally, we demonstrate that by adding ''realistic'' terms to the t-J model Hamiltonian, we can easily destroy the d x 2 Ϫy 2 ground state. This casts doubt on the robustness of the d x 2 Ϫy 2 state as the ground state in a microscopic model for the hightemperature superconductors.

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Exact-diagonalization demonstration of incommensurability and the associated Fermi surface forNholes in thet-Jmodel

Cited by 32 publications

References 43 publications

On the contrasting spin dynamics of La_2-xSr_xCuO₄, Nd_2-xCe_xCuO₄and YBa₂Cu₃O_6+xnear half filling

On the contrasting spin dynamics of La_2-xSr_xCuO₄, Nd_2-xCe_xCuO₄and YBa₂Cu₃O_6+xnear half filling

Antiferromagnetism and superconductivity of the two-dimensional extended t-J model

Low-energy states with different symmetries in thet−Jmodel with two holes on a 32-site lattice

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Exact-diagonalization demonstration of incommensurability and the associated Fermi surface forNholes in thet-Jmodel

Cited by 32 publications

References 43 publications

On the contrasting spin dynamics of La2-xSrxCuO4, Nd2-xCexCuO4and YBa2Cu3O6+xnear half filling

On the contrasting spin dynamics of La2-xSrxCuO4, Nd2-xCexCuO4and YBa2Cu3O6+xnear half filling

Antiferromagnetism and superconductivity of the two-dimensional extended t-J model

Low-energy states with different symmetries in thet−Jmodel with two holes on a 32-site lattice

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Product

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On the contrasting spin dynamics of La_2-xSr_xCuO₄, Nd_2-xCe_xCuO₄and YBa₂Cu₃O_6+xnear half filling

On the contrasting spin dynamics of La_2-xSr_xCuO₄, Nd_2-xCe_xCuO₄and YBa₂Cu₃O_6+xnear half filling