Fig. 2: Bi-stability of the unit cell under compression.
From: Programmable and robust static topological solitons in mechanical metamaterials
a Schematic of the unit cell and the corresponding theoretical model. The simplified theoretical model consisting of elastic rods and neck springs (yellow and magenta dots) is illustratively superimposed on the unit cell of the sample. b The on-site potential \({{\mathcal{P}}}_{{\rm{cell}}}\left(\delta ;\theta \right)\) of the unit cell under vertical compression strain \(\varepsilon =10.7 \% \). c Two possible buckling configurations (polarization states) of the unit cell corresponding to the two equilibrium states of the double-well potential shown in b.
