On-site attractive multiorbital Hamiltonian for d-wave superconductors

Article

关键词: ELECTRONIC-STRUCTURE;    PHASE-SEPARATION;    HUBBARD;    SYMMETRY;    STATE;    MODEL;   

DOI  :  10.1103/PhysRevB.93.224519

来源: SCIE

【 摘 要 】

We introduce a two-orbital Hamiltonian on a square lattice that contains on-site attractive interactions involving the two e(g) orbitals. Via a canonical mean-field procedure similar to the one applied to the well-known negative-U Hubbard model, it is shown that the model develops d-wave (B-1g) superconductivity with nodes along the diagonal directions of the square Brillouin zone. This result is also supported by exact diagonalization of the model in a small cluster. The expectation is that this relatively simple attractive model could be used to address the properties of multiorbital d-wave superconductors in the same manner that the negative-U Hubbard model is widely applied to the study of the properties of s-wave single-orbital superconductors. In particular, we show that by splitting the e(g) orbitals and working at three-quarters filling, such that the x(2) - y(2) orbital dominates at the Fermi level but the 3z(2) - r(2) orbital contribution is nonzero, the d-wave pairing state found here phenomenologically reproduces several properties of the superconducting state of the high T(c)d cuprates.

【 授权许可】

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