论文标题
跨浆果 - 偶极转变的外在和内在的非线性霍尔效应
Extrinsic and Intrinsic Nonlinear Hall Effects across Berry-Dipole Transitions
论文作者
论文摘要
三维HOPF绝缘子是超出十倍分类的一类拓扑阶段。将两个旋转不变的HOPF绝缘体具有不同HOPF不变式的临界点与通常的Dirac-type或Weyl-Type临界点完全不同，并且以量化的浆果偶极子的特征。接近此类浆果 - 偶极转变，我们发现弱掺杂方案中的外在和内在的非线性霍尔电导率张量的特征是掺杂水平和块状能量之间的两个通用功能，并且与整个过渡过程中的HopF不变性中的变化成正比。我们的工作表明，非线性霍尔效应在浆果 - 偶极转变之间表现出通用量的量化行为，从而在非线性霍尔效应和HOPF不变性之间建立了对应关系。
Three-dimensional Hopf insulators are a class of topological phases beyond the tenfold-way classification. The critical point separating two rotation-invariant Hopf insulator phases with distinct Hopf invariants is quite different from the usual Dirac-type or Weyl-type critical points and uniquely characterized by a quantized Berry dipole. Close to such Berry-dipole transitions, we find that the extrinsic and intrinsic nonlinear Hall conductivity tensors in the weakly doped regime are characterized by two universal functions of the ratio between doping level and bulk energy gap, and are directly proportional to the change in Hopf invariant across the transition. Our work suggests that the nonlinear Hall effects display a general-sense quantized behavior across Berry-dipole transitions, establishing a correspondence between nonlinear Hall effects and Hopf invariant.
