Magnetism-mediated transition between crystalline and higher-order topological phases in NpSb

• DOI: 10.1103/physrevb.103.195152
• Publication Date: 2021-05-24T14:29:13Z
• Authors: Ning Mao; Xiangting Hu; Hao Wang; Ying Dai; Baibiao Huang; Yuriy Mokrousov; Chengwang Niu
• Keywords: Magnetism; Topological insulator

Merging the fields of topology and magnetism expands scope fundamental quantum phenomena with novel functionalities for topological spintronics enormously. Here, we theoretically demonstrate that ferromagnetism provides an efficient means to achieve a switching between crystalline higher-order insulator phases in two dimensions. Using tight-binding model first-principles calculations, identify layered NpSb as long-awaited two-dimensional intrinsic ferromagnetic order band gap which is large 220 meV. We show when ${\mathcal{M}}_{z}$ symmetry preserved out plane magnetization this material, it exhibits pair gapless edge states along all boundaries carries nonzero mirror Chern number ${\mathcal{C}}_{\mathcal{M}}=1$. Remarkably, rotating into phase parity-based invariant ${\ensuremath{\nu}}_{2\text{D}}=1$ achieved, in-gap corner emerge. Our results pave way understanding engineering insulating ferromagnets.