We present a parallel algorithm for numerical calculations for electronic lattice models with interactions and disorder. In this scheme, diagonal and off-diagonal disorder are treated exactly per disorder configuration and interaction effects are evaluated using conserving approximations based on self-consistent perturbation theory. We demonstrate this method by calculating second-order corrections to the local pairing amplitude and specific heat for the attractive Hubbard model.

International Journal of Modern Physics BOct 10, 20010 citations

Spin-Mediated Electron Pairing II

Frederick J. Mayer

International Journal of Physics Study and ResearchMar 18, 20240 citations

Journal of Low Temperature Physics

Effects of disorder on the electron pairing

Raúl Oviedo‐Roa, C. Wang, Oracio Navarro

Published Nov 1, 1996• 4 citations

Publisher

DOI: 10.1007/bf00768458

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Pairing correlations with s* and dx2−y2 symmetry in a disordered Cu4 O8 cluster

Владимир Федорович Елесин, Arkady V. Krasheninnikov, L. А. Openov

Recently we have shown [V. F. Elesin, A. V. Krasheninnikov, and L. A. Openov, Sov. Phys. JETP 79, 789 (1994)] that in the hole-doped ${\mathrm{Cu}}_{4}$ ${\mathrm{O}}_{8}$ cluster pairing correlations with ${s}^{*}$ symmetry are nearly twice as strong as those with ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ symmetry, while in the electron-doped cluster pairing correlations seem to be present in the ${s}^{*}$ channel only. In this paper the effect of on-site disorder on the pairing correlators with ${s}^{*}$ and ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ symmetry in the ${\mathrm{Cu}}_{4}$ ${\mathrm{O}}_{8}$ cluster is studied numerically through an exact diagonalization of the Emery-Anderson Hamiltonian. It is shown that at a nearly optimal doping level (0.25 excess holes per copper atom) the disorder weakens pairing correlations in the ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ channel and has much less influence on pairing correlations in the ${s}^{*}$ channel. Based on the results obtained, the "superconducting" components of pairing correlators are estimated to be 10-30% of their full values, with the remaining parts of correlators being contributions from a finite-size effect. These results indicate that cluster calculations may be relevant for the study of high- ${T}_{c}$ superconductivity.Recently we have shown [V. F. Elesin, A. V. Krasheninnikov, and L. A. Openov, Sov. Phys. JETP 79, 789 (1994)] that in the hole-doped ${\mathrm{Cu}}_{4}$${\mathrm{O}}_{8}$ cluster pairing correlations with ${s}^{*}$ symmetry are nearly twice as strong as those with ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ symmetry, while in the electron-doped cluster pairing correlations seem to be present in the ${s}^{*}$ channel only. In this paper the effect of on-site disorder on the pairing correlators with ${s}^{*}$ and ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ symmetry in the ${\mathrm{Cu}}_{4}$${\mathrm{O}}_{8}$ cluster is studied numerically through an exact diagonalization of the Emery-Anderson Hamiltonian. It is shown that at a nearly optimal doping level (0.25 excess holes per copper atom) the disorder weakens pairing correlations in the ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ channel and has much less influence on pairing correlations in the ${s}^{*}$ channel. Based on the results obtained, the "superconducting" components of pairing correlators are estimated to be 10-30% of their full values, with the remaining parts of correlators being contributions from a finite-size effect. These results indicate that cluster calculations may be relevant for the study of high-${T}_{c}$ superconductivity.

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A Parallel Algorithm for Conserving Approximation of Lattice Models Having Both Interactions and Disorder

B. Buhrow, J. J. Deisz

International Journal of Modern Physics BOct 10, 20010 citations

Spin-Mediated Electron Pairing II

Frederick J. Mayer

International Journal of Physics Study and ResearchMar 18, 20240 citations

We derive an analytical theory for two interacting electrons in a

d

-dimensional random potential. Our treatment is based on an effective random matrix Hamiltonian. After mapping the problem on a nonlinear $\ensuremath{\sigma}$ model, we exploit similarities with the theory of disordered metals to identify a scaling parameter, investigate the level correlation function, and study the transport properties of the system. In agreement with recent numerical work we find that pair propagation is subdiffusive and that the pair size grows logarithmically with time.

Recently we have shown [V. F. Elesin, A. V. Krasheninnikov, and L. A. Openov, Sov. Phys. JETP 79, 789 (1994)] that in the hole-doped

{\mathrm{Cu}}_{4}

{\mathrm{O}}_{8}

cluster pairing correlations with

{s}^{*}

symmetry are nearly twice as strong as those with ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ symmetry, while in the electron-doped cluster pairing correlations seem to be present in the

{s}^{*}

channel only. In this paper the effect of on-site disorder on the pairing correlators with

{s}^{*}

and ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ symmetry in the

{\mathrm{Cu}}_{4}

{\mathrm{O}}_{8}

cluster is studied numerically through an exact diagonalization of the Emery-Anderson Hamiltonian. It is shown that at a nearly optimal doping level (0.25 excess holes per copper atom) the disorder weakens pairing correlations in the ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ channel and has much less influence on pairing correlations in the

{s}^{*}

channel. Based on the results obtained, the "superconducting" components of pairing correlators are estimated to be 10-30% of their full values, with the remaining parts of correlators being contributions from a finite-size effect. These results indicate that cluster calculations may be relevant for the study of high-

{T}_{c}

superconductivity.