论文标题
kagome semimetal mn $ _3 $ ge的外延薄膜中大型异常的Nernst and Reverse Spin-Hall效应
Large anomalous Nernst and inverse spin-Hall effects in epitaxial thin films of Kagome semimetal Mn$_3$Ge
论文作者
论文摘要
拓扑材料的晶体定义明确的薄膜的合成对于揭开其中尺度量子特性和设备应用非常重要。 Mn $ _3 $ ge是一种抗铁磁性Weyl半学，在Kagome晶格上具有手性磁性结构，预计将在费米能量附近的Weyl节点周围具有增强的浆果曲率，从而导致较大的异常霍尔 / Nernst效应和大型旋转效果。使用磁控溅射，我们已经种植了六角形D0 $ _ {19} $ mn $ _3 $ ge的外世薄膜，该薄膜是平坦而连续的。在热电和自旋泵送设备中观察到大型异常的NERNST和逆旋转效果。我们的MN $ _3 $ GE膜中的异常Nernst信号估计为0.1 $μ$ V / k，尽管Mn $ _3 $ _3 $ ge在室温下的弱磁化强度约为3.5 m $μ_b$，但在铁磁Fe中也可比。旋转混合电导率为90.5 nm $^{ - 2} $在py / mn $ _3 $ ge接口上，Mn $ _3 $ ge中的自旋 - 霍尔角估计约为pt中的8倍。
Synthesis of crystallographically well-defined thin films of topological materials is important for unraveling their mesoscale quantum properties and for device applications. Mn$_3$Ge, an antiferromagnetic Weyl semimetal with a chiral magnetic structure on a Kagome lattice, is expected to have enhanced Berry curvature around Weyl nodes near the Fermi energy, leading to large anomalous Hall / Nernst effects and a large spin-Hall effect. Using magnetron sputtering, we have grown epitaxial thin films of hexagonal D0$_{19}$ Mn$_3$Ge that are flat and continuous. Large anomalous Nernst and inverse spin-Hall effects are observed in thermoelectric and spin-pumping devices. The anomalous Nernst signal in our Mn$_3$Ge films is estimated to be 0.1 $μ$V / K, and is comparable to that in ferromagnetic Fe, despite Mn$_3$Ge having a weak magnetization of ~3.5 m$μ_B$ at room temperature. The spin mixing conductance is 90.5 nm$^{-2}$ at the Py / Mn$_3$Ge interface, and the spin-Hall angle in Mn$_3$Ge is estimated to be about 8 times of that in Pt.
