STRONGLY CORRELATED ELECTRONS

    In the last years, there has been considerable interest in unconventional pairing mechanisms to explain the physics of the high critical temperature superconducting materials. In particular, there is important evidence for d-wave superconductivity in the high-Tc cuprates, and for triplet pairing in ruthenates and quasi one-dimensional organic systems like (TMTSF)2CF4.
    Because of its simplicity, the Hubbard model has been widely studied as a generic model for strongly correlated systems. However, this model is rather disappointing regarding superconductivity. In 1D for repulsive on-site interaction U, it is known that there is no region of doping for which some pairing correlation function dominates at large distances, while only s-wave pairing is obtained for negative U. In 2D all the numerical works devoted to search signatures of superconductivity for positive U have been negative so far.
    I am studying:

  • Phase diagrams of extended Hubbard models.

    Recent publications:
  • Incommmensurability and unconventional superconductor to insulator transition in the Hubbard model with bond-charge interaction
    A. A. Aligia, A. Anfossi, L. Arrachea, C. Degli Esposti Boschi, A. O. Dobry, C. Gazza, A. Montorsi, F. Ortolani, M. E. Torio
    Physical Review Letters 99, 206401 (2007). cond-mat/0704.0717
  • U-J Synergy Effect for the High Tc Superconductors
    Liliana Arrachea and Drazen Zanchi.
    Phys. Rev. B 71, 064519 (2005).
  • d-wave superconductivity in the effective extended Hubbard model for cuprates.
    Liliana Arrachea and A. A. Aligia.
    Physica C 224, 408 (2004).
  • Qualitative understanding of the sign of t ' asymmetry in the extended t-J model and relevance for pairing properties.
    G.B. Martins, J. C. Xavier, L. Arrachea and E. Dagotto.
    Physical Review B (RC) 64, 180513 (2001).
  • Pairing correlations in electron-doped cuprates.
    A. A. Aligia and L. Arrachea.
    Physical Review B 64, 214518 (2001).
  • Pairing correlations in a generalized Hubbard model for the cuprates.
    Liliana Arrachea and A. A. Aligia.
    Physical Review B 61, 9686 (2000).
  • Triplet superconductivity in quasi one-dimensional systems.
    A. A. Aligia and Liliana Arrachea.
    Physical Review B 60, 15332 (1999).
  • d(x2-y2) superconductivity in a generalized Hubbard model.
    Liliana Arrachea and A. A. Aligia.
    Physical Review B 59, 1333 (1999).