论文标题
Dirac Line-node半法中的可调旋转大厅和旋转的Nernst效果
Tunable spin Hall and spin Nernst effects in Dirac line-node semimetals XCuYAs (X=Zr, Hf; Y=Si, Ge)
论文作者
论文摘要
第四纪砷化合物Xcuyas（X = Zr，Hf; Y = SI，GE）属于1111型季季化合物的广大家族，其具有出色的物理性能，范围从$ P $ P $ - 类型的透明半导体到高高的FE基于Fe的超级负责人。在本文中，我们根据密度功能理论计算研究了这些化合物中的电子结构拓扑，旋转霍尔效应（SHA）和旋转的Nernst效应（SNE）。首先，我们发现所考虑的四种化合物是狄拉克半学分，沿着布里远的区域边界边界$ a $ a $ -m $ a $ a $ a $ a $ a $ a $ $ r $和低密度状态（dos）（dos）（$ e_f $）（$ e_f $）沿着布里渊区域边界$ a $ a $ -m $ a $ a $ -m $ a $ a $ a $ a $ a $ a $ a $ a $ a $ a $ a $ a $ a $ a $ m $ a $ a $ a $ m $ a $ a $ a $ m $ a $ a $ a $ m $ a $ a $ a $ a $ a $ m $ - $ m $ - 其次，发现其中一些被认为的化合物中的固有的她和SNE很大。特别是，HFCUGEAS的计算出的旋转厅电导率（SHC）高达-514（$ \ hbar $/e）（s/cm）。 Hfcugeas在室温下的旋转Nernst电导率（SNC）也很大，为-0.73（$ \ hbar $/e）（a/m -k）。此外，可以通过改变施加的电场方向或旋转电流方向来操纵SHC和SNC的大小和符号。这些化合物中的SHE和SNE也可以通过化学掺杂或电控来调整费米水平来增强。 Finally, a detailed analysis of the band-decomposed and $k$-resolved spin Berry curvatures reveals that these large SHC and SNC as well as their notable tunabilities originate largely from the presence of a large number of spin-orbit coupling-gapped Dirac points near the Fermi level as well as the gapless Dirac line-nodes, which give rise to large spin Berry curvatures.因此，我们的发现表明，这四种Xcuyas化合物不仅为探索她，SNE和乐队拓扑之间的相互作用提供了一个有价值的平台，而且在旋转型和旋转热量旋转方面具有有希望的应用。
The quaternary arsenide compounds XCuYAs (X=Zr, Hf; Y= Si, Ge) belong to the vast family of the 1111-type quaternary compounds, which possess outstanding physical properties ranging from $p$-type transparent semiconductors to high-temperature Fe-based superconductors. In this paper, we study the electronic structure topology, spin Hall effect (SHE) and spin Nernst effect (SNE) in these compounds based on density functional theory calculations. First we find that the four considered compounds are Dirac semimetals with the nonsymmorphic symmetry-protected Dirac line nodes along the Brillouin zone boundary $A$-$M$ and $X$-$R$ and low density of states (DOS) near the Fermi level ($E_F$). Second, the intrinsic SHE and SNE in some of these considered compounds are found to be large. In particular, the calculated spin Hall conductivity (SHC) of HfCuGeAs is as large as -514 ($\hbar$/e)(S/cm). The spin Nernst conductivity (SNC) of HfCuGeAs at room temperature is also large, being -0.73 ($\hbar$/e)(A/m-K). Moreover, both the magnitude and sign of the SHC and SNC in these compounds can be manipulated by varying either the applied electric field direction or spin current direction. The SHE and SNE in these compounds can also be enhanced by tuning the Fermi level via chemical doping or electric gating. Finally, a detailed analysis of the band-decomposed and $k$-resolved spin Berry curvatures reveals that these large SHC and SNC as well as their notable tunabilities originate largely from the presence of a large number of spin-orbit coupling-gapped Dirac points near the Fermi level as well as the gapless Dirac line-nodes, which give rise to large spin Berry curvatures. Our findings thus suggest that the four XCuYAs compounds not only provide a valuable platform for exploring the interplay between SHE, SNE and band topology but also have promising applications in spintronics and spin caloritronics.
