论文标题
两轨系统的Hund物理景观
Hund physics landscape of two-orbital system
论文作者
论文摘要
由于最近在无限层中发现超导性的动机，镍$ _ {1-δ} $ sr $_Δ$_Δ$ nio $ _2 $（re $ = $ = $ = $ nd，pr），我们研究了Hund在四分之一填充的两官型Hubbard模型中的hund bupling $ j $在peripery上的作用。该模型的负面有效库仑相互作用的区域揭示了与典型的洪德金属活性填充物中的三轨和五轨模型区分开。我们确定了独特的机制，包括四种不同的相关金属，其中一种源于莫特绝缘子的接近度，而其他三种金属（我们称之为“中间”金属，弱的金属金属和价值金属，均来自$ j $的效果。建议定义表征这些金属的标准，从而在两轨系统中建立了Hund的金属性的存在。
Motivated by the recent discovery of superconductivity in infinite-layer nickelates RE$_{1-δ}$Sr$_δ$NiO$_2$ (RE$=$Nd, Pr), we study the role of Hund's coupling $J$ in a quarter-filled two-orbital Hubbard model which has been on the periphery of the attention. A region of negative effective Coulomb interaction of this model is revealed to be differentiated from three- and five-orbital models in their typical Hund's metal active fillings. We identify distinctive regimes including four different correlated metals, one of which stems from the proximity to a Mott insulator while the other three, which we call "intermediate" metal, weak Hund's metal, and valence-skipping metal, from the effect of $J$ being away from Mottness. Defining criteria characterizing these metals are suggested, establishing the existence of Hund's metallicity in two-orbital systems.
