Interplay of magnetism and band structure in EuCd2As2

EuCd2As2 has emerged as a topological material where magnetism may produce strong band structure effects. This compound has been understood as a candidate Weyl semimetal, based mostly on transport and photoemission measurements. I will present our recent results on samples of controlled carrier concentration through chemical synthesis. We find magneto-optical evidence of a sizeable band gap, remarkably sensitive to the local Eu magnetism. Our results contradict the current consensus on the ground state of this compound, bringing into question its topological nature.