Large anisotropic magnetoresistance in $α$-MnTe induced by strain

α-MnTe is a p-type semiconducting altermagnet with a Néel temperature near 300K. Due to the strong spin-orbit coupling and the altermagnetic symmetry, Kramers degeneracy is lifted in the valence band maxima along the $Γ$-K line and the A point. However, the energy difference is found to be small, and any small shift in the spectrum can dramatically change the overall transport behavior. Here we show that a strain modulating the [0001] axis of the unit cell by ~±0.5% can significantly change the transport signature, switching the thermal window between the two regions of the valence band. When the $Γ$-K line is dominating, the planar Hall effect and the anisotropic magnetoresistance can be modulated by an order of magnitude, with the maximum up to ~30%.