Charge dynamics of a noncentrosymmetric magnetic Weyl semimetal

Abstract

Abstract The interplay of topology with magnetism in Weyl semimetals recently arose to a vanguard topic, because of novel physical scenarios with anomalous transport properties. Here, we address the charge dynamics of the noncentrosymmetric and ferromagnetic (T C ~ 15 K) PrAlGe material and discover that it harbours electronic correlations, which are reflected in a sizeable reduction of the Fermi velocity with respect to the bare band value at low temperatures (T). At T < T C, the optical response registers a band reconstruction, which additionally causes a reshuffling of spectral weight, pertinent to the electronic environment of the type-I Weyl fermions and tracing the remarkable anomalous Hall conductivity (AHC). With the support of first-principles calculations, we provide evidence for the intimate relationship between a topological resonance of the absorption spectrum and the progressively enhanced occupation of non-trivial states with large Berry curvatures, a requirement for AHC.