Journal article

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

  • Yue, Changming Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
  • Hoshino, Shintaro Department of Physics, Saitama University, Saitama 338-8570, Japan
  • Werner, Philipp Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
Published in:
  • Physical Review B. - 2020, vol. 102, no. 19, p. 195103
English 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≲n≤3 and ferro-orbital order dominates the strongly interacting region for 1≲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.
Faculté des sciences et de médecine
Département de Physique
  • English
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