论文标题
在极地抗铁磁铁bamnsb $ _2 $
Bulk quantum Hall effect of spin-valley-coupled Dirac fermions in a polar antiferromagnet BaMnSb$_2$
论文作者
论文摘要
拓扑材料中相对论狄拉克/韦伊尔准粒子的非常规特征最明显地表现在2D量子厅效应（QHE）中，它们的旋转和/或山谷极化进一步丰富了它们的品种。尽管它扩展到三个维度已经长期以来一直在启发理论建议，但候选人缺乏物质候选者。 Here we have discovered valley-contrasting spin-polarized Dirac fermions in a multilayer form in bulk antiferromagnet BaMnSb$_2$, where the out-of-plane Zeeman-type spin splitting is induced by the in-plane inversion symmetry breaking and spin-orbit coupling (SOC) in the distorted Sb square net.此外，我们已经观察到定义明确的量化霍尔高原，以及在低温下消失的层间电导率，这是半成员QHE的标志，以散装形式。发现每一层的大厅电导率几乎量化为$ 2（n+1/2）e^2/h $，$ n $是Landau指数，这与受强旋转旋转 - Valley偶联保护的两个自旋偏置的Dirac Valleys是一致的。
Unconventional features of relativistic Dirac/Weyl quasi-particles in topological materials are most evidently manifested in the 2D quantum Hall effect (QHE), whose variety is further enriched by their spin and/or valley polarization. Although its extension to three dimensions has been long-sought and inspired theoretical proposals, material candidates have been lacking. Here we have discovered valley-contrasting spin-polarized Dirac fermions in a multilayer form in bulk antiferromagnet BaMnSb$_2$, where the out-of-plane Zeeman-type spin splitting is induced by the in-plane inversion symmetry breaking and spin-orbit coupling (SOC) in the distorted Sb square net. Furthermore, we have observed well-defined quantized Hall plateaus together with vanishing interlayer conductivity at low temperatures as a hallmark of the half-integer QHE in a bulk form. The Hall conductance of each layer is found to be nearly quantized to $2(N+1/2)e^2/h$ with $N$ being the Landau index, which is consistent with two spin-polarized Dirac valleys protected by the strong spin-valley coupling.
