Spin dynamics of a magnetic Weyl semimetal SrMnSb

Cai, Z.*; Bao, S.*; Wang, W.*; Ma, Z.*; Dong, Z.-Y.*; Shangguan, Y.*; Wang, J.*; Ran, K.*; Li, S.*; Kamazawa, Kazuya*; Nakamura, Mitsutaka   ; Adroja, D.*; Yu, S.-L.*; Li, J.-X.*; Wen, J.*

Dirac matters provide a platform for exploring the interplay of their carriers with other quantum phenomena. SrMnSb has been proposed to be a magnetic Weyl semimetal and provides an excellent platform to study the coupling between Weyl fermions and magnons. We performed inelastic neutron scattering measurements on single crystals of SrMnSb, and found The dispersion in the magnetic Mn layer extends up to about 76 meV, while that between the layers has a narrow band width of 6 meV. Despite the coexistence of Weyl fermions and magnons, we find no clear evidence that the magnetic dynamics are influenced by the Weyl fermions in SrMnSb, possibly because that the Weyl fermions and magnons reside in the Sb and Mn layers separately, and the interlayer coupling is weak due to the quasi-two-dimensional nature of the material.