Extended Data Fig. 9: Fully-relativistic Kohn-Sham DFT band structures of bulk CrSBr with 1.5% uniaxial strain applied along the a axis.

a, AFM CrSBr with magnetic moment constrained along the easy b axis. b, c, d, FM CrSBr with magnetic moment constrained along the b, a, and c axes, respectively. Due to the stronger interlayer hybridization in the FM phase, the top valence band and bottom conduction band at Gamma split into subband groups, resulting in a smaller Kohn-Sham band gap than that of the AFM phase. Once in the FM phase, the bandgap shows no appreciable difference when the magnetic moment is aligned along the different axes. These features agree well with our strain and magnetic field dependent measurements. We note, however, that Kohn-Sham DFT at the mean-field level has been known to underestimate the band gaps of semiconductors, and the band gaps presented here should not be directly compared to the PL energy levels in the present work. Optimized norm-conserving Vanderbilt pseudopotentials are employed in the fully-relativistic calculations with similar generation parameters to the scalar-relativistic pseudopotentials.