Fig. 2: Cleavage process and stability assessment for the wz monolayers.
From: Multiferroicity and giant in-plane negative Poisson’s ratio in wurtzite monolayers
a Cleavage process for (110) plane monolayer ZnX (X = S, Se, Te) with layer thickness from 4L to 8L, which indicates the monotonically increasing cleavage energy with layer thickness and that the energy drops dramatically at the moment of cleaving off due to the interface reconstruction. The inset shows the gradually localized charge (ρ = 0.065 eÅ−3) from S to Te for ZnX. b Atomic bonding landscape from interior to surface for 6L (12 atomic-thickness) ZnSe, which indicates the weakened surface bonding strength with gradually stretching until the separation of the outermost layer. c, d Phonon spectrum and AIMD simulation for monolayer ZnSe, which suggests that the monolayer structure is stable with non-imaginary frequency phonon dispersion and no phase change.
