Figure 3.

Evolution of potential energy curve on the Q_LS coordinate along the ferroelectric switching directions under (a,b) x-polarized and (c,d) y-polarized pulse. Rapidly oscillating Q_IRx under pulse modulates the potential energy curve (grey lines) with respect to the static case at Q_IR = 0 Å$\sqrt{\mu }$ (bold black line). The effective potential energy experienced by the Q_LS is the time-average of the potential energy curves (orange line). 〈Φ〉 is the effective energy barrier under the pulse while Φ₀ is pristine energy barrier. Direction and relative magnitude of the effective anharmonic force F_anh on Q_LS are depicted by the orange arrow. (e) Effective interlayer interaction between the Mo and S sublattices induced by Q_IR. (f) Contour plot of the interaction energy indicates the direction and relative magnitude of the anharmonic force depending on the polarization direction of Q_IR.