A publication with Jairo Sinova, Libor Šmejkal, Anna Hellenes and Rafael González Hernández about the observation of a spontaneous anomalous Hall response in the Mn5Si3 d-wave altermagnet candidate has been published in Nature Communications.
Phases with spontaneous time-reversal symmetry (T) breaking are sought after for their anomalous physical properties, low-dissipation electronic and spin responses, and information-technology applications. Recently predicted altermagnetic phase features an unconventional and attractive combination of a strong T-symmetry breaking in the electronic structure and a zero or only weak-relativistic magnetization. In this work, they experimentally observe the anomalous Hall effect, a prominent representative of the T-symmetry breaking responses, in the absence of an external magnetic field in epitaxial thin-film Mn5Si3 with a vanishingly small net magnetic moment. By symmetry analysis and first-principles calculations they demonstrate that the unconventional d-wave altermagnetic phase is consistent with the experimental structural and magnetic characterization of the Mn5Si3epilayers, and that the theoretical anomalous Hall conductivity generated by the phase is sizable, in agreement with experiment. An analogy with unconventional d-wave superconductivity suggests that our identification of a candidate of unconventional d-wave altermagnetism points towards a new chapter of research and applications of magnetic phases.