Santos-Cottin, D.Mohelsky, I.Wyzula, J.Le Mardele, F.Kapon, I.Nasrallah, S.Barisic, N.Zivkovic, ISoh, J. R.Guo, FeiRigaux, K.Puppin, MicheleDil, J. H.Gudac, B.Rukelj, Z.Novak, M.Kuzmenko, A. B.Homes, C. C.Dietl, TomaszOrlita, M.Akrap, Ana2024-02-202024-02-202024-02-202023-11-0310.1103/PhysRevLett.131.186704https://infoscience.epfl.ch/handle/20.500.14299/204362WOS:001101160800004EuCd2As2 is now widely accepted as a topological semimetal in which a Weyl phase is induced by an external magnetic field. We challenge this view through firm experimental evidence using a combination of electronic transport, optical spectroscopy, and excited-state photoemission spectroscopy. We show that the EuCd2As2 is in fact a semiconductor with a gap of 0.77 eV. We show that the externally applied magnetic field has a profound impact on the electronic band structure of this system. This is manifested by a huge decrease of the observed band gap, as large as 125 meV at 2 T, and, consequently, by a giant redshift of the interband absorption edge. However, the semiconductor nature of the material remains preserved. EuCd2As2 is therefore a magnetic semiconductor rather than a Dirac or Weyl semimetal, as suggested by ab initio computations carried out within the local spin-density approximation.Physical SciencesInterband Faraday-RotationExchange InteractionsMagnetoresistanceEutetext::journal::journal article::research article