Mario Novak (University of Zagreb): Interplay between spin and charge in Europium-based semimetals and semiconductors

In this seminar, I will discuss our recent work on the Eu-based compound EuCd₂As₂ and its relation to isostructural compounds. Particular attention will be given to EuCd₂As₂, a material widely regarded as a topological semimetal in which a Weyl phase is expected to emerge under an external magnetic field. In our recent study published in Phys. Rev. Lett. 131, 186704 (2023), we challenge this prevailing view by presenting compelling experimental evidence obtained through a combination of electronic transport, optical spectroscopy, and photoemission spectroscopy. Our results reveal that EuCd₂As₂ is, in fact, a magnetic semiconductor with a gap of 0.77 eV, in striking contrast to predictions from numerous ab initio calculations within the local spin-density approximation.
I will also discuss the rich magnetotransport and magnetostriction phenomena observed in this compound, as well as recent intriguing findings in EuAg₄Sb₂, a material hosting a spin moiré superlattice. Finally, I will present how Eu–Sr substitution influences the magnetic and transport properties in both systems.

Zoom Information:

https://us02web.zoom.us/j/2022111100

(Meeting code: 2022111100 Password: skcm2)