Strain-tunable altermagnetic α-MnTe thin films*

Altermagnetic α-MnTe thin films exhibit a tunable anomalous Hall effect (AHE) controlled by epitaxial strain and field cooling. We present resonant inelastic X-ray scattering (RIXS) and X-ray magnetic circular dichroism (XMCD) measurements on MnTe films with different strain states: field-cooled (FC) and zero-field-cooled (ZFC) films grown on GaAs(111), and a more bulk-like reference film on SrF₂(111). 

Our RIXS energy maps at the Mn L₃ edge reveal systematic changes in the dd excitations between samples, indicating strain-dependent modifications to the Mn local environment. Circular dichroism in the RIXS magnetic excitations is consistent with the presence of spontaneous shear strain in our samples. XMCD measurements are discussed in the context of how field cooling and strain affect DMI and spin canting in the presence of external fields. The combined spectroscopic results demonstrate that epitaxial strain and field-cooling procedures modify both the local electronic structure and magnetic ordering in MnTe films. Our findings suggest that the onset of bilinear Dzyaloshinskii-Moriya interactions can be used to control and tune the AHE towards antiferromagnetic spintronic applications.