Chiral Magnon Mixing by Symmetry-Breaking in Collinear Ferrimagnets

Abstract

Magnons in ferromagnets possess spin angular momentum defined by right-handed precession of the moment around the magnetization direction. In antiferromagnets with no net magnetization, left-and right-handed magnons are degenerate in the absence of an applied field. Ferrimagnets possess uncompensated magnetic sublattices, which should natively possess right-and left-handed magnons where their energy is split by the internal molecular field. Here, we show that RMn6Sn6 (R = Tb, Er) ferrimagnets possess right and left-handed magnon bands that cross at finite momentum (k) within the basal plane, defining modes with opposite dynamical chirality. Depending on the symmetry of the ferrimagnetic order, which may be manipulated by varying the rare-earth magnetic anisotropy or with applied field, the band crossing may remain a nodal line or may be gapped. The gapped modes contain hybridized chiral excitations whose chirality becomes k-dependent.

References in corpus (15)

• Quantum magnonics: when magnon spintronics meets quantum information science
• Discovery of a quantum limit Chern magnet TbMn6Sn6
• Rare earth engineering in RMn${}_6$Sn${}_6$ topological kagome magnets
• Chiral-Split Magnon in Altermagnetic MnTe
• Magnon-squeezing as a niche of quantum magnonics
• Anisotropically large anomalous and topological Hall effect in a kagome magnet
• Switching magnon chirality in artificial antiferromagnet
• Symmetry breaking induced magnon-magnon coupling in synthetic antiferromagnets
• Interplay between magnetism and band topology in Kagome magnets $R$Mn${}_6$Sn${}_6$
• Magnetic chirality as probed by neutron scattering
• Topological Hall effect induced by chiral fluctuations in ErMn6Sn6
• New insight into tuning magnetic phases of $R$Mn${}_6$Sn${}_6$ kagome metals
• Orbital character of the spin-reorientation transition in TbMn${}_6$Sn${}_6$
• High-field magnetic phase diagrams of the $\text{R}$Mn${}_6$Sn${}_6$ kagome metals
• Magnetic Structures and Spin-wave Excitations in Rare-Earth Iron Garnets near the Compensation Temperature