Conversion of chiral phonons into magnons in antiferromagnets

Chiral phonons with atomic rotations converted into electron spins result in a change of spin magnetizations in crystals [1,2]. In this talk, we investigate a new conversion of chiral phonons into magnons in antiferromagnets by a spin-wave model with exchange and Dzyaloshinskii-Moriya interactions. The atomic rotations in chiral phonons are treated as slow phonons, which modulate spin-spin interactions and induce time-dependent magnon excitations due to geometric effect within the adiabatic approximation. Here, we demonstrate that a non-trivial change of the number of magnons needs to break the spin-rotation symmetry around the quantization axis. As a result, the clockwise and counterclockwise chiral phonons induce a change of the number of magnons with opposite signs, which corresponds to an increasing or decreasing spin magnetization due to the chiral nature of phonons. Meanwhile, a non-zero net magnetization can be generated by the proposed effect in antiferromagnets.

[1] M. Hamada and S. Murakami, Phys. Rev. Research 2, 023275 (2020).

[2] D. Yao and S. Murakami, Phys. Rev. B 105, 184412 (2022).