论文标题
横向热电传导率的增强，起源于节点线的固定点
Enhancement of transverse thermoelectric conductivity originating from stationary points in nodal line
论文作者
论文摘要
由于最近在Co $ _2 $ mnga，fe $ _3x $（$ x $ = al，GA）和CO $ _3 $ _3 $ sn $ _2 $ _2 $ _2 $中发现的大量异常的Nernst效果的动机，我们进行了第一些原始研究，以澄清横向热elect $ nimogage的起源（$ inogy）$ inogy firciples firciples forem form forme forem in forem forem forem n in in forem forem in of therveers forem in forem forem in forem forem in of thereforce forem in ynemeT（$ i）。 $α_{ij} $的内在贡献可以从费米级别的浆果曲率（$ω$）来理解，而$ω$沿着节点线（在没有旋转轨道耦合的情况下）在Brilliouin Zone中沿节点线（在没有旋转轨道耦合的情况下是无间隙）。我们发现，不仅Weyl点，而且在节点分散的能量分散体中的固定点起着至关重要的作用。固定点使投射到节点线上的状态的密度中尖锐的峰，清楚地识别了$α_{ij} $最大增强的特征性费米能。我们还发现$α_{ij}/t $打破了莫特的关系，并在这些能量处显示出特殊的温度依赖性。目前的结果表明，固定点将为我们提供有用的指导原理，以设计磁铁，显示出较大的异常效果。
Motivated by the recent discovery of a large anomalous Nernst effect in Co$_2$MnGa, Fe$_3X$ ($X$=Al, Ga) and Co$_3$Sn$_2$S$_2$, we performed a first-principles study to clarify the origin of the enhancement of the transverse thermoelectric conductivity ($α_{ij}$) in these ferromagnets. The intrinsic contribution to $α_{ij}$ can be understood in terms of the Berry curvature ($Ω$) around the Fermi level, and $Ω$ is singularly large along nodal lines (which are gapless in the absence of the spin-orbit coupling) in the Brillouin zone. We find that not only the Weyl points but also stationary points in the energy dispersion of the nodal lines play a crucial role. The stationary points make sharp peaks in the density of states projected onto the nodal line, clearly identifying the characteristic Fermi energies at which $α_{ij}$ is most dramatically enhanced. We also find that $α_{ij}/T$ breaks the Mott relation and show a peculiar temperature dependence at these energies. The present results suggest that the stationary points will give us a useful guiding principle to design magnets showing a large anomalous Nernst effect.
