Epitaxial growth of thin films of Mn5Si3, an altermagnetic candidate with remarkable properties for spintronics

The SPIXY team at CINaM has pioneered the epitaxial growth of monocrystalline Mn5Si3 thin films that have been studied by a Franco-German-Czech consortium. These films, although devoid of magnetization like antiferromagnets, display a robust anomalous Hall effect, like ferromagnets. This combination of properties is unique to altermagnetism, which emerges from the singular symmetries of spin structure. An altermagnet is composed of a set of magnetic moments alternately oriented in opposite directions, like a collinear antiferromagnet. But, in contrast to it, the two sub-arrays of moments in an altermagnet do not have the same electronic environment, so they are linked by rotational symmetry rather than translational or inversion symmetry. As a result, the electric current is polarized by a spin splitting of the band structure, rather like ferromagnets.

Moreover, Mn5Si3 has the great advantage of being made of light elements, i.e. with low spin-orbit coupling. This enables us to unequivocally link its altermagnetic character to its specific crystalline symmetry that is stabilized by growth engineering in our molecular beam epitaxy chamber. Last but not least, Mn5Si3 is composed of abundant, inexpensive elements. Theory, specific crystalline structure, strong Hall effect in the absence of magnetic field and magnetization, coupled with a clear influence of crystallinity, are all signatures of Mn5Si3’s altermagnetism. They are the topic of this pioneering paper, published in arXiv barely a year after the theoretical prediction of altermagnetism.

Publication:

  1. Reichlová, R. Lopes Seeger, R. González-Hernández, I. Kounta, R. Schlitz, D. Kriegner, P. Ritzinger, M. Lammel, M. Leiviskä, V. Petříček, P. Doležal, E. Schmoranzerová, A. Bad’ura, A. Thomas, V. Baltz, L. Michez, J. Sinova, S.T.B. Goennenwein, T. Jungwirth, L. Šmejkal, Observation of a spontaneous anomalous Hall response in the Mn5Si3 d-wave altermagnet candidate, Nature Communications 15, 4961 ( 2024)