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arXiv · 2502.19738

Ferroelectric Chirality-Driven Direction-Tunable and Spin-Invertible Corner States in 2D MOF-Based Magnetic Second-Order Topological Insulators

Jialin Gong·Wei Sun·Yang Wu·Zhenzhou Guo·Shifeng Qian·Xiaotian Wang·Gang Zhang
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Abstract

Despite the rapid progress in predicting 2D magnetic second-order topological insulators (SOTIs), effective strategies for manipulating their spin-polarized corner states remain largely unexplored. The interplay between ferroelectricity, chirality, magnetism, and topology presents an untapped opportunity for controlling these corner states. Here, we propose a novel approach for tuning spin-polarized corner states in 2D magnetic SOTIs by inducing ferroelectric chirality in 2D metal-organic frameworks (MOFs) with intrinsic structural flexibility. Through symmetry analysis, we strategically replace pyrazine (pyz) ligands with 2-pyrazinolate (2-pyzol) ligands in the 2D MOF Cr(pyz)2, leading to the emergence of a new 2D magnetic SOTI, Cr(2-pyzol)2, which facilitates ferroelectric chirality controlled spin-polarized corner states in both spin channels. Through first-principle calculations, we demonstrate that Cr(2-pyzol)2 belongs to ferroelectric chiral systems, and its corner states can be directionally tuned in real space and spin-inverted in spin space upon ferroelectric chirality switching. Our work represents the first attempt to simultaneously manipulate corner states in both real space and spin space, offering a new strategy for integrating ferroelectric chirality into 2D MOF-based magnetic SOTIs.

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Jialin Gong, Wei Sun, Yang Wu, Zhenzhou Guo, Shifeng Qian, Xiaotian Wang, Gang Zhang. 2025-02-27. Ferroelectric Chirality-Driven Direction-Tunable and Spin-Invertible Corner States in 2D MOF-Based Magnetic Second-Order Topological Insulators. https://arxiv.org/abs/2502.19738

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