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Magnon-induced phononic Chern insulator
Rui-Chang Shen, Yihao Yang, Haoran Xue
TL;DR
GHz topological phononics needs a compact, low-loss route to complete Chern gaps. This paper uses phase-winding magnon–phonon coupling in a honeycomb crystal to induce Haldane-type complex hopping, yielding tunable phononic Chern phases and experimentally resolvable gaps.
Problem
Realizing complete Chern phononic gaps at GHz frequencies remains challenging despite the integration advantages of high-frequency artificial phononic crystals.
Method
The paper places ferromagnetic islands at honeycomb plaquette centers so circular Kittel modes couple to surrounding phonons with phase winding, then derives the resulting effective phonon model.
Results
The coupling opens a full phononic Chern gap, produces effective Haldane-type complex hoppings, and supports phases with Chern numbers tunable up to |C|=2.
Takeaways & Limitations
Chiral magnon–phonon hybridization provides a magnetically tunable route to topological phononics with phonon-dominated transport and gaps suitable for GHz acoustic devices.
Takeaways & Limitations
The phonon-dominated effective description assumes large detuning, |δω| ≫ g, t.
Abstract
from arXiv · showhide
High-frequency artificial phononic crystals offer a low-loss platform compatible with on-chip integration, yet realizing Chern phononic phases at GHz frequencies remains challenging. Here, we propose a magnon-induced phononic Chern insulator in a honeycomb phononic crystal hybridized with ferromagnetic islands at the hexagon centers. A circularly polarized Kittel mode couples to the surrounding phonons with a phase winding, which breaks time-reversal symmetry and opens a full Chern gap. In the large-detuning regime, this mechanism leads to an effective Haldane-type phononic model with magnon-induced complex hopping. By tuning the magnon-phonon interaction, the full hybrid system accesses Chern phases with tunable Chern numbers |C|=1 and |C|=2. The predicted gaps can exceed realistic phonon and magnon linewidths, enabling their observation in GHz acoustic devices. Our work establishes chiral magnon--phonon hybridization as a route to magnetically reconfigurable topological phononics.