Entropy and electronic orders of the three-orbital Hubbard model with antiferromagnetic Hund coupling
Entropy and electronic orders of the three-orbital Hubbard model with antiferromagnetic Hund coupling
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DOI：
10.1103/physrevb.102.195103
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发表时间：
2020-07
影响因子：
3.7
通讯作者：
C. Yue;S. Hoshino;P. Werner
中科院分区：
文献类型：
--
作者：
C. Yue;S. Hoshino;P. Werner
多轨道Hubbard系统中的反铁磁Hund耦合导致轨道冻结和相关的超导不稳定性，以及在奇数轨道的情况下的独特的复合订单。虽然半满三轨道模型的富相图最近已被详细探讨，掺杂系统的性质仍有待澄清。在这里，我们通过计算半填充模型的熵来补充以前的研究，该模型表现出轨道冻结区域的增加和复合有序相的抑制。掺杂相关的相图表明，复合有序状态可以稳定在掺杂的莫特制度，如果传统的电子秩序被抑制的挫折。当反铁轨道序在填充区2\ensuremath {\lesssim}n\ensuremath{\le}3$占主导地位，铁轨道序在强相互作用区1\ensuremath {\lesssim} nl 2 $占主导地位时，我们发现在n=1.5$（四分之一填充）附近有一个非常高的${T}_{c}$.在掺杂体系中，轨道冻结交叉与超导电性之间也存在着密切的联系。
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 $2\ensuremath{\lesssim}n\ensuremath{\le}3$ and ferro-orbital order dominates the strongly interacting region for $1\ensuremath{\lesssim}nl2$, we find superconductivity with a remarkably high ${T}_{c}$ around $n=1.5$ (quarter filling). Also in the doped system, there is a close connection between the orbital-freezing crossover and superconductivity.