  The origin of anomalous Hall effect (AHE) in magnetic materials is one of the
most intriguing aspect in condensed matter physics and has been controversial
for a long time. Recent studies indicate that the intrinsic AHE is closely
related to the Berry curvature of occupied electronic states. In a magnetic
Weyl semimetal with broken time-reversal symmetry, there are significant
contributions on Berry curvature around Weyl nodes, which would lead to a large
intrinsic AHE. Here, we report the large intrinsic AHE in the half-metallic
ferromagnet Co3Sn2S2 single crystal. By systematically mapping out the
electronic structure of Co3Sn2S2 theoretically and experimentally, the large
intrinsic AHE should originate from the Weyl fermions near the Fermi energy.
Furthermore, the intrinsic anomalous Hall conductivity depends linearly on the
magnetization and this can be attributed to the sharp decrease of magnetization
and the change of topological characteristics.
