Ryuichi Shindou, Ryo Matsumoto, Shuichi Murakami
Topological phases have been explored in various fields in physics such as spintronics, photonics, liquid helium, correlated electron system and cold-atomic system. This leads to the recent foundation of emerging materials such as topological band insulators, topological photonic crystals and topological superconductors/superfluid. Here, we propose topological magnonic crystal which provides protected chiral edge modes for magnetostatic spin waves. Based on a generic linearized Landau-Lifshitz equation, we show that a magnonic crystal with the dipolar interaction usually acquires spin wave band with non-zero Chern integer. We argue that such magnonic systems are accompanied by the same integer numbers of chiral magnonic edge modes, along which the spin wave can propagate in a unidirectional manner without being backward scattered. Being a robust `one-way spin-wave guide', the proposed chiral magnonic edge mode makes it possible the magnonic Fabry-Perot type interferometer, which can be utilized as the spin-wave logic gate.
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http://arxiv.org/abs/1204.3349
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