论文标题
受对称保护的拼变磁性Weyl节点回路和多向脉冲节点，$ 5D^n $ cubic double double perovskites $（n = 1,2）$
Symmetry-protected Spinful Magnetic Weyl Nodal Loops and Multi-Weyl Nodes in $5d^n$ Cubic Double Perovskites $(n=1,2)$
论文作者
论文摘要
Using both an effective three-band model and {\it ab initio} calculations, we have investigated various topological features in the cubic ferromagnetic $5d^{1,2}$ systems showing large spin-orbit coupling (SOC): Ba$_2$NaOsO$_6$, Sr$_2$SrOsO$_6$, and Ba$_2$$B$ReO$_6$ （$ b $ = mg，Zn）。在有时间反转对称性（$ {\ cal t} $）的情况下，以$ w $点相互链接的无旋Dirac节点环出现在镜像飞机上。值得注意的是，打破$ {\ cal t} $会导致稀疏的磁性Weyl节点环（MWNL），即使在大SOC和相关强度$ u $变化也是由于镜子对称性和损坏的$ {\ cal t} $而导致的。此外，有两种类型的磁性Weyl点，带有手性费用$ |χ| = 1，2 $沿$ C_ {4V} $对称线，另一个包围区域中心的II类型MWNL，取决于$ U $。此外，铁磁ba $ _2 $ znreo $ _6 $是一个理想的半份半学，在费米水平上，没有拓扑琐碎的散装状态，在费米级别上有MWNL和磁性Weyl节点。这些系统产生了一个非常大的异常霍尔电导率$σ_{xy} $，最高为1160（$ω$ cm）$^{ - 1} $。我们的发现可能广泛适用于具有立方（或略微扭曲）类似FCC的结构的$ T_ {2G} $系统。
Using both an effective three-band model and {\it ab initio} calculations, we have investigated various topological features in the cubic ferromagnetic $5d^{1,2}$ systems showing large spin-orbit coupling (SOC): Ba$_2$NaOsO$_6$, Sr$_2$SrOsO$_6$, and Ba$_2$$B$ReO$_6$ ($B$= Mg, Zn). In the presence of time-reversal symmetry (${\cal T}$), spinless Dirac nodal loops linked to each other at the $W$ points appear in the mirror planes. Remarkably, breaking ${\cal T}$ leads to spinful magnetic Weyl nodal loops (MWNLs) that are robust even at large SOC and correlation strength $U$ variation due to the combination of mirror symmetry and broken ${\cal T}$. Additionally, there are two types of magnetic Weyl points with chiral charges $|χ|=1, 2$ along the $C_{4v}$ symmetry line, and another type-II MWNL encircling the zone center, that are dependent on $U$. Furthermore, the ferromagnetic Ba$_2$ZnReO$_6$ is an ideal half semimetal with MWNLs and magnetic Weyl nodes at the Fermi level without the interference of topologically trivial bulk states. These systems give rise to a remarkably large anomalous Hall conductivity $σ_{xy}$ of up to 1160 ($Ω$cm)$^{-1}$. Our findings may apply widely for $t_{2g}$ systems with cubic (or slightly distorted) fcc-like structures.
