EuCd2As2 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 {\em ab initio} computations carried out within the local spin-density approximation.
Cite
@article{arxiv.2301.08014,
title = {EuCd$_2$As$_2$: a magnetic semiconductor},
author = {D. Santos-Cottin and I. Mohelský and J. Wyzula and F. Le Mardelé and I. Kapon and S. Nasrallah and N. BarišIć and I. Živković and J. R. Soh and F. Guo and K. Rigaux and M. Puppin and J. H. Dil and B. Gudac and Z. Rukelj and M. Novak and A. B. Kuzmenko and C. C. Homes and Tomasz Dietl and M. Orlita and Ana Akrap},
journal= {arXiv preprint arXiv:2301.08014},
year = {2023}
}
Comments
Accepted for publication in Physical Review Letters