Microscopic origin of the magnetic interactions and their experimental signatures in altermagnetic La$_2$O$_3$Mn$_2$Se$_2$

Laura Garcia-Gassull; Aleksandar Razpopov; Panagiotis Peter Stavropoulos; Igor I Mazin; Roser Valentí

doi:10.1038/s44306-025-00125-9

paper

Microscopic origin of the magnetic interactions and their experimental signatures in altermagnetic La $_{2}$ O $_{3}$ Mn $_{2}$ Se $_{2}$

arXiv:2506.21661 · doi:10.1038/s44306-025-00125-9

Abstract

Altermagnets (AM) are a recently introduced type of magnets, with no net magnetization like antiferromagnets, but displaying a non-relativistic Zeeman splitting in reciprocal space like ferromagnets. One of the lately discussed models to realize AM is the inverse Lieb lattice (ILL). Initially suggested as a purely theoretical construct, the ILL occurs in real materials such as La $_{2}$ O $_{3}$ Mn $_{2}$ Se $_{2}$ . However, AM on the ILL requires 90 $^{\circ}$ nearest-neighbor superexchange to be {\it antiferromagnetic} and dominant over the 180 $^{\circ}$ next-nearest-neighbor superexchange, in apparent contradiction to the Goodenough-Kanamori-Anderson (GKA) rules. Yet, AM ordering was found to be the ground state in La $_{2}$ O $_{3}$ Mn $_{2}$ Se $_{2}$ . Combining ab initio and analytical methods, we determine how direct exchange and superexchange act together to produce a large antiferromagnetic nearest-neigbor coupling. The seeming contradiction with the GKA rules is traced back to the multiorbital character of Mn $^{+ 2}$ ions. By calculating magnon bands, we identify universal signatures of the exchange interactions, suggesting experimental fingerprints.

8 pages, 4 figures + references and supplemental information

Microscopic origin of the magnetic interactions and their experimental signatures in altermagnetic La $_{2}$ O $_{3}$ Mn $_{2}$ Se $_{2}$

Abstract

References in corpus (15)

Cited by in corpus (2)

Microscopic origin of the magnetic interactions and their experimental signatures in altermagnetic La2​O3​Mn2​Se2​

Abstract

References in corpus (15)

Cited by in corpus (2)

Microscopic origin of the magnetic interactions and their experimental signatures in altermagnetic La $_{2}$ O $_{3}$ Mn $_{2}$ Se $_{2}$