Spin separation and filtering assisted by topological corner states in the Kekul\'{e} lattice
Abstract
Higher-order topological corner states have been realized in two-dimensional Kekul\'{e} lattice, which can be further coupled with spin polarization through the implementation of local magnetization. In this work, we numerically investigate the spin-dependent transport properties assisted by topological corner states in the Kekul\'{e} lattice. By applying local magnetization and electric potential, the topological corner states are spin polarized with opposite spins localized at different corners, thereby demonstrating a spin-corner state locking mechanism. Transport characteristics, including transmission, local density of states, and local current density, are calculated for a two-terminal setup consisting of a diamond-shaped Kekul\'{e} lattice connected to two leads. When opposite local magnetization is applied to the corners, spin-up and spin-down electrons are perfectly separated, forming two spin-polarized conducting channels and leading to spin spatial separation. In the presence of identical local magnetization on both corners and an electric potential at one corner, the spin-polarized corner states can facilitate selective filtering of different spins and generate spin-polarized currents by tuning the energy. Furthermore, spin-resolved transmission diagrams as functions of both the Fermi energy and electric potential are presented, illustrating the global distribution of spin filtering through topological corner states.
Cite
@article{arxiv.2502.09879,
title = {Spin separation and filtering assisted by topological corner states in the Kekul\'{e} lattice},
author = {Kai-Tong Wang and Hui Wang and Shijie Liu and Miaomiao Wei and Fuming Xu},
journal= {arXiv preprint arXiv:2502.09879},
year = {2025}
}