DCMP Seminar: Mario Novak

Department of Condensed Matter Physics invites you to lecture

Mario Novak (University of Zagreb, Croatia):
Europium-based topological semimetals and magnetic semiconductors

In this seminar, I will discuss our recent work on Eu-based compounds, with a particular focus on EuCd₂As₂, a material widely regarded as a topological semimetal in which a Weyl phase emerges 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 excited-state photoemission spectroscopy. Our results demonstrate that EuCd₂As₂ is, in fact, a magnetic semiconductor with a gap of 0.77 eV—significantly different from predictions made by many ab initio calculations within the local spin-density approximation. In addition, I will present our recent magnetotransport measurements, which reveal colossal negative magnetoresistance and an anomalous Hall effect in insulating samples of EuCd₂As₂, as well as other intriguing Eu-based compounds.

This lecture was supported by the project QM4ST (Quantum materials for applications in sustainable technology), reg. no. CZ.02.01.01/00/22_008/0004572, cofunded by the ERDF from the Programme Johannes Amos Commenius, call Excellent Research.