Fig. 6. DFT calculations explaining the origin of a higher transition temperature at the surface.

a exchange pathways for J₁, J₂, J₃ and J₆, overlaid on the CrSBr crystal structure. U-dependence of b, T_CW c, J₁ d, J₂, and e, J₃ for S1: bulk CrSBr (red), S2: rigid monolayer (orange), S3: fixed ab monolayer (blue) and S4: free monolayer (green). ${\mathrm{\Delta }}_{\mathrm{S}1\to \mathrm{S}2}$: change in T_CW and corresponding J from bulk to rigid monolayer. ${\mathrm{\Delta }}_{\mathrm{S}2\to \mathrm{S}3}$: change in T_CW and corresponding J from rigid monolayer to fixed ab monolayer.