Weyl fermions and spin dynamics of metallic ferromagnet SrRuO3.
Weyl fermions that emerge at band crossings in momentum space caused by the spin-orbit interaction act as magnetic monopoles of the Berry curvature and contribute to a variety of novel transport phenomena such as anomalous Hall effect and magnetoresistance. However, their roles in other physical properties remain mostly unexplored. Here, we provide evidence by neutron Brillouin scattering that the spin dynamics of the metallic ferromagnet SrRuO3 in the very low energy range of milli-electron volts is closely relevant to Weyl fermions near Fermi energy. Although the observed spin wave dispersion is well described by the quadratic momentum dependence, the temperature dependence of the spin wave gap shows a nonmonotonous behaviour, which can be related to that of the anomalous Hall conductivity. This shows that the spin dynamics directly reflects the crucial role of Weyl fermions in the metallic ferromagnet.
Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba 305-0801, Japan.|Department of Materials Structure Science, School of High Energy Science, Graduate University for Advanced Science, Tsukuba 305-0801, Japan.
Shinichi
S
Itoh
Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba 305-0801, Japan.|RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan.
Yasuo
Y
Endoh
Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba 305-0801, Japan.|Department of Materials Structure Science, School of High Energy Science, Graduate University for Advanced Science, Tsukuba 305-0801, Japan.
Tetsuya
T
Yokoo
Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba 305-0801, Japan.
Soshi
S
Ibuka
Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea.|Center for Correlated Electron Systems, Institute for Basic Science, Seoul 151-747, Korea.
Je-Geun
JG
Park
RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan.
Yoshio
Y
Kaneko
RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan.
Kei S
KS
Takahashi
RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan.|Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan.
Yoshinori
Y
Tokura
RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan.|Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan.
Naoto
N
Nagaosa