Fig. 5

Schematic phase diagram for Weyl fermions in heavy fermion systems. Illustration of the evolution of the contributions from different experimental probes of Weyl fermions in heavy fermion systems; the chiral anomaly c_a, electronic specific heat C_e, and topological Hall effect \(\rho _{{xy}}^{\mathrm{T}}\). When the electronic bands in the vicinity of the Weyl points become heavy at low temperatures, the massive reduction of the effective Fermi velocity v^* leads to the chiral anomaly contribution c_a becoming undetectable, yet gives a significant contribution from Weyl nodes to the electronic specific heat C_e, which is otherwise not detectable in weakly correlated materials. Meanwhile the topological Hall effect \(\rho _{{xy}}^{\mathrm{T}}\) which arises from the Berry curvature can be detected both when the f-electrons are well localized, as well as deep inside the heavy fermion state