Entropy and electronic orders of the three-orbital Hubbard model with antiferromagnetic Hund coupling

Article

关键词: SUPERCONDUCTIVITY;    FERMIONS;    LATTICE;    IQIST;   

DOI  :  10.1103/PhysRevB.102.195103

来源: SCIE

【 摘 要 】

An antiferromagnetic Hund coupling in multiorbital Hubbard systems induces orbital freezing and an associated superconducting instability, as well as unique composite orders in the case of an odd number of orbitals. While the rich phase diagram of the half-filled three-orbital model has recently been explored in detail, the properties of the doped system remain to be clarified. Here, we complement the previous studies by computing the entropy of the half-filled model, which exhibits an increase in the orbital-frozen region and a suppression in the composite ordered phase. The doping-dependent phase diagram shows that the composite ordered state can be stabilized in the doped Mott regime, if conventional electronic orders are suppressed by frustration. While antiferro-orbital order dominates the filling range 2 less than or similar to n <= 3 and ferro-orbital order dominates the strongly interacting region for 1 less than or similar to n < 2, we find superconductivity with a remarkably high Tc around n = 1.5 (quarter filling). Also in the doped system, there is a close connection between the orbital-freezing crossover and superconductivity.

【 授权许可】

Free