Comparative study of the effect of magnetic order on charge dynamics in Weyl semimetals PrAlSi and PrAlGe

PrAlSi and PrAlGe are Weyl semimetal undergoing ferromagnetic transitions below 20 K. The potential coupling between the magnetic moments of Pr³⁺ ions and the Dirac fermions, and more broadly the implications of ferromagnetic order on the band structure and hence, electronic excitations in these materials are still being explored. We present a comparative study of charge dynamics, in the spectral range from 80 cm^-1 to 24,000 cm^-1 and at various temperatures across the magnetic transition, between PrAlSi and PrAlGe. We performed reflectance measurements and from Kramers-Kronig transformation extract various optical functions. In this talk, we focus in particular on optical conductivity, and the dielectric and loss functions, showing very similar evolution with cooling through the magnetic transition, although at different energy scales and of different magnitudes. We further discuss their implications in terms of the differences between the electronic band structures of PrAlSi and PrAlGe.