High bosonic Bott index and transport of multi-band topological magnons

Kai Tao Huang; X. S Wang

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arXiv · 2512.24184

High bosonic Bott index and transport of multi-band topological magnons

Kai Tao Huang·X. S Wang

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Abstract

Magnons are bosonic quasiparticles in magnetically ordered systems. Bosonic Bott index has been affirmed as a real-space topological invariant for a two-band ferromagnetic model. In this work,we theoretically investigate the topology and transport of magnons in a multi-band bosonic Kagome ferromagnetic model. We demonstrate the validity of the bosonic Bott indices of values larger than 1 in multi-band magnonic systems by showing the agreement with Chern numbers in the clean limit and the bulk-boundary correspondence during the topological phase transition. For the high Bott index phase, the disorder-induced topological phase transition occurs in a multi-step manner. Using a generalized Landauer-Buttiker formalism, we reveal how the magnon transport depends on Gilbert damping and disorder under coherent excitation or temperature difference. The results further justify the bosonic Bott index as a robust real-space topological invariant for multi-band magnonic systems and provide insights into the transport of topological magnons.

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Kai Tao Huang, X. S Wang. 2025-12-30. High bosonic Bott index and transport of multi-band topological magnons. https://arxiv.org/abs/2512.24184

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