Non-Hermitian Moiré Valley Filter

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Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2024-04-12
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Language
en
Pages
7
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Physical Review Letters, Volume 132, issue 15, pp. 1-7
Abstract
A valley filter capable of generating a valley-polarized current is a crucial element in valleytronics, yet its implementation remains challenging. Here, we propose a valley filter made of a graphene bilayer which exhibits a 1D moiré pattern in the overlapping region of the two layers controlled by heterostrain. In the presence of a lattice modulation between layers, electrons propagating in one layer can have valley-dependent dissipation due to valley asymmetric interlayer coupling, thus giving rise to a valley-polarized current. Such a process can be described by an effective non-Hermitian theory, in which the valley filter is driven by a valley-resolved non-Hermitian skin effect. Nearly 100% valley polarization can be achieved within a wide parameter range and the functionality of the valley filter is electrically tunable. The non-Hermitian topological scenario of the valley filter ensures high tolerance against imperfections such as disorder and edge defects. Our work opens a new route for efficient and robust valley filters while significantly relaxing the stringent implementation requirements.
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Citation
Shao, K, Geng, H, Liu, E, Lado, J, Chen, W & Xing, D Y 2024, ' Non-Hermitian Moiré Valley Filter ', Physical Review Letters, vol. 132, no. 15, 156301, pp. 1-7 . https://doi.org/10.1103/PhysRevLett.132.156301