Observation of mechanical kink control and generation via phonons

Kinks are localized transitions between distinct ground states that are associated with a topological charge, significant in fields ranging from condensed matter to cosmology. Theoretical and computational studies have shown that phonons can interact with mechanical kinks to trigger their motion, offering a pathway for kink control. However, the discreteness of most kink-supporting systems introduces a Peierls-Nabarro (PN) barrier, requiring extra energy for kinks to move locally. Here, we report the first experimental observation of mechanical kink control and generation via phonons. To achieve this, we create an elastically-coupled realization of the Kane-Lubensky chain model, which supports a single, topologically protected kink that requires zero energy to deform quasi-statically, resulting in a zero PN barrier. In addition to finding strong agreement between our experiments and numerical simulations, we also numerically observe unique kink dynamics distinct from other nonlinear discrete systems, including continuously smoothly varying set of kink solutions between the neighboring onsite-centered kinks (and associated “shape” mode evolution) and long-duration kink motion, the latter of which has important implications for kink control. Given the topological polarization of our system and the associated features, this work has implications for remote material stiffness control, locomotion, shape-shifting materials, as well as robust signal processing and transmission.