Magnetotransport Hysteresis in Semiconducting α-MnTe Thin Films at Different Doping Concentrations*

The new class of collinear magnetic materials, “altermagnets”^[1], display zero global magnetization and exhibit anomalous Hall and Kerr effects due to the symmetry connecting magnetic sublattices. This unconventional combination of properties is promising for novel applications in antiferromagnetic spintronics^[2]. One predicted semiconducting candidate, α-MnTe, is accessible for magnetotransport studies. While initial reports of bulk crystals^[3] and thin films on InP and SrF2^[4] report altermagnetism in MnTe, there remains a need for more diverse experimental observations. Our study investigates fully relaxed α-MnTe thin films grown by MBE on GaAs(111). Magnetotransport experiments are configured with the current along either the [11-20] or [1-100] direction of MnTe, and the field is applied between this and the [0001] direction. We observe these films to be p-type with varying carrier concentrations (1.03E19 - 4.84E19 cm^-3) and mobilities (17.9 - 96.8 cm²V^-1s-¹). We observe hysteresis in both transverse and longitudinal resistance. This is accompanied by a weak signal (<0.66 μ_B/Mn) in SQUID magnetometry at fields up to 7T. Our measurements explore the dependence of the transport hysteresis on doping concentration and help address gaps in our understanding of the role of the chemical environment and doping on the altermagnetism of MnTe.

1. Phys Rev X, 12(4):040501

2. Phys Lett A, 382(13):865–871

3. arXiv:2310.09134

4. Phys Rev Lett, 130(3):036702