近日，中国人民大学卢仲毅团队研究了非常规磁性中高自旋陈恩数的堆叠诱导2型量子自旋霍尔绝缘子。2026年4月9日出版的《科学通报》杂志发表了这项成果。

虽然堆叠两个第一类量子自旋霍尔绝缘体通常会产生平庸绝缘体，但第二类量子自旋霍尔绝缘体组装体的行为尚未被探索。

研究组基于格点模型的计算，证明堆叠两个第二类量子自旋霍尔绝缘体并不会产生平庸绝缘体，而是形成一个具有高自旋陈数的非平庸量子自旋霍尔绝缘体。在此相中，两对具有相反手性和极化的拓扑边缘态在边界上共存。该计算进一步揭示，双层的量子化自旋霍尔电导率是单层的两倍。当存在U(1)对称性时，高自旋陈数相保持稳定；当U(1)对称性被破坏时，该相在广泛的参数范围内仍然存在。

此外，基于第一性原理电子结构计算，研究组证明双层Nb₂SeTeO在交变磁性和非常规补偿磁性中是一种具有高自旋陈数的第二类量子自旋霍尔绝缘体。再者，将此策略扩展到多层堆叠自然会产生具有更高自旋陈数的量子自旋霍尔绝缘体。该工作不仅加深了对第一类和第二类量子自旋霍尔绝缘体之间区别的理解，而且为实现高度量子化的自旋霍尔电导率提供了一条途径。

附：英文原文

Title: Stacking-induced type-II quantum spin Hall insulators with high spin Chern number in unconventional magnetism

Author: Fengjie Ma c d, Peng-Jie Guo a b, Zhong-Yi Lu a b e

Issue&Volume: 2026/04/09

Abstract: While stacking two type-I quantum spin Hall insulators typically results in a trivial insulator, the behavior of the assembly of type-II quantum spin Hall insulators remains unexplored. In this article, based on calculations of a lattice model, we demonstrate that stacking two type-II quantum spin Hall insulators does not yield a trivial insulator but instead forms a nontrivial quantum spin Hall insulator with high spin Chern number. In this phase, two pairs of topological edge states with opposite chirality and polarization coexist at the boundary. Our calculations further reveal that the quantized spin Hall conductivity of the bilayer is twice that of the monolayer. When U(1) symmetry is present, the high spin Chern number phase remains stable; when U(1) symmetry is broken, it persists over a broad parameter range. Furthermore, based on first-principles electronic structure calculations, we demonstrate that bilayer Nb2SeTeO is a type-II quantum spin Hall insulator with a high spin Chern number in altermagnetism and unconventional compensated magnetism. Moreover, extending this strategy to multilayer stacks naturally leads to a quantum spin Hall insulator with a higher spin Chern number. Our work not only deepens the distinction between type-I and type-II quantum spin Hall insulators, but also offers a route toward realizing highly quantized spin Hall conductivity.

DOI: 10.1016/j.scib.2026.04.018

Source: https://www.sciencedirect.com/science/article/abs/pii/S2095927326003804