Magnon corner states in twisted bilayer honeycomb magnets
Abstract
Search for higher-order topological insulators, characterized by topologically protected gapless boundary states of codimension higher than one, in bosonic systems has attracted growing interest. Here, we establish twisted bilayer honeycomb magnets as a new platform for hosting second-order topological magnon insulators (SOTMIs) without fine-tuning. We employ a simple, minimal Heisenberg spin model to describe misaligned bilayer sheets of honeycomb ferromagnetic magnets with a large commensurate twist angle. We found that the higher-order topology in this bilayer system shows a significant dependence on the interlayer exchange coupling. The SOTMI, featuring topologically protected magnon corner states, appears for ferromagnetic interlayer couplings, while the twisted bilayer exhibits a nodal phase in the case of antiferromagnetic interlayer coupling.
Keywords
Cite
@article{arxiv.2202.12151,
title = {Magnon corner states in twisted bilayer honeycomb magnets},
author = {Chun-Bo Hua and Feiping Xiao and Zheng-Rong Liu and Jin-Hua Sun and Jin-Hua Gao and Chui-Zhen Chen and Qingjun Tong and Bin Zhou and Dong-Hui Xu},
journal= {arXiv preprint arXiv:2202.12151},
year = {2023}
}
Comments
Accepted for publication as a Letter in Phys. Rev. B