Research

Theoretical prediction and experimental observation of anomalous Hall effect in altermagnetic candidate composed of light elements Mn and Si

In our collaborative effort with groups from Prague, Mainz, Grenoble, Marseille and Dresden, we have observed spontaneous anomalous Hall effect and compensated magnetization consistent with our first-principle prediction of sizable anomalous Hall conductivity in Mn5Si3 material. Demonstration of the dissipationless transport in compensated magnet Mn5Si3 opens theoretical and experimental reserach of quantum and topological transport in materials with light and abundantant elements wihtout relying on heavy and often toxic elements or large magnetic fields. Our study also suggest Mn5Si3 as candidate for unconvenitonal magnetic phases including d-wave altermagnetism.

Publications

  • H. Reichlová, R. L. Seeger, R. González-Hernández, I. Kounta, R. Schlitz, D. Kriegner, P. Ritzinger, M. Lammel, M. Leiviskä, A. Birk Hellenes, K. Olejník, V. Petříček, P. Doležal, L. Horak, E. Schmoranzerová, A. Baďura, S. Bertaina, A. Thomas, V. Baltz, L. Michez, J. Sinova, S. T. B. Goennenwein, T. Jungwirth, and L. Šmejkal

    Observation of a spontaneous anomalous Hall response in an unconventional d-wave altermagnet candidate

    Nature Communications 15 (2024) 4961(1)-4961(10)

Image by Anna Birk Hellenes and Libor Šmejkal.

Observation of altermagnetic electronic structure

Together with researchers from Czechia, Switzerland, Germany, and Austria we have experimentally observed altermangetic band spin splitting theoretically proposed by us few years ago. We have studied high quality crystals of semiconducting MnTe and probed electronic strucutre by photoemission measurements on synchrotron. The resulting experimental band strucutre shows outstanding match to our first principle prediction. 

Publications

  • J. Krempaský*, L. Šmejkal*, S. W. D'Souza*, M. Hajlaoui, G. Springholz, K. Uhlířová, F. Alarab, P. C. Constantinou, V. Strokov, D. Usanov, W. R. Pudelko, R. González-Hernández, A. Birk Hellenes, Z. Jansa, H. Reichlová, Z. Šobáň, R. D. Gonzalez Betancourt, P. Wadley, J. Sinova, D. Kriegner, J. Minár, J. H. Dil, T. Jungwirth

    Altermagnetic lifting of Kramers spin degeneracy

    Nature 626 (2024) 517-522.