Manganese telluride (MnTe) is a relatively well-known material [1] whose antiferromagnetic and semiconducting properties make it relevant for various applications, notably including spintronics [2]. Renewed interest in its study arose with recent experimental observations comprising anomalous Hall effect [3], anisotropic magnetoresistance [4] and its altermagnetic character [5].  

The main part of the presentation concerns results of a magnetic field magnon energy dependence obtained through THz spectroscopy measurements for various canting angles of magnetic field vector relative to the sample normal and anisotropy hard axis. Linear spin wave theory (LSWT), whose main aspects are discussed in detail in this part, is utilized for the description and exploration of related MnTe magnon physics.

In the last section, two additional points of interest regarding recent MnTe measurements are presented: Observed asymmetry of left- and right-circularly polarised THz wave transmission and temperature dependence of magnon energies, which requires extending the used model beyond LSWT.

References:

[1] J. Allen, G. Lucovsky, and J. Mikkelsen, Optical properties and electronic structure of crossroads material MnTe, Solid State Commun. 24, 367 (1977).
[2] V. Baltz, A. Manchon, M. Tsoi, T. Moriyama, T. Ono, and Y. Tserkovnyak, Antiferromagnetic spintronics, Rev. Mod. Phys. 90, 015005 (2018).
[3] N. Nagaosa, J. Sinova, S. Onoda, A. H. MacDonald, and N. P. Ong, Anomalous Hall effect, Rev. Mod. Phys. 82, 1539 (2010).
[4] P. Ritzinger and K. Vyborny, Anisotropic magnetoresistance: materials, models and applications, R. Soc. Open Sci. 10, 230564 (2023).
[5] Z. Liu, M. Ozeki, S. Asai, S. Itoh, and T. Masuda, Chiral split magnon in altermagnetic MnTe, Phys. Rev. Lett. 133, 156702 (2024).