Description
Altermagnets are collinear compensated magnets in which opposite-spin sublattices are related by crystal point-group symmetries, such as rotations or mirrors, leading to momentum-dependent spin splitting even in the absence of spin–orbit coupling, while maintaining zero net magnetization. CrSb (NiAs-type, P63/mmc, TN ~ 700 K) has emerged as a prototypical metallic g-wave altermagnet, with spin splitting in the electronic bands confirmed by ARPES [2, 3]. The analogous splitting in the magnon spectrum — a complementary collective-mode signature — has only very recently been reported [1, 4].
Here we use high-resolution time-of-flight inelastic neutron scattering on co-aligned CrSb single crystals to characterize the magnon dispersion in the HK0 reciprocal-space plane and along the A–M high-symmetry direction. A minimal Heisenberg model quantitatively reproduces (i) an energy-dependent splitting of the magnon arc that grows monotonically from 0.030 to 0.105 r.l.u. between 165 and 215 meV; (ii) a two-peak
structure resolved along A–M, further confirming the altermagnetic magnon splitting; and (iii) the absence of splitting along the symmetry-degenerate (H, −2H, 0) direction, providing an independent symmetry-based confirmation of the altermagnetic model
