Guided accumulation of active particles by topological design of a second-order skin effect

Understand

Collective guidance of out-of-equilibrium systems without using external fields is a challenge of paramount importance in active matter, ranging from bacterial colonies to swarms of self-propelled particles.

• Designing strategies to guide active matter and exploiting enhanced diffusion associated to its motion will provide insights for application from sensing, drug delivery to water remediation.
• However, achieving directed motion without breaking detailed balance, for example by asymmetric topographical patterning, is challenging.
• Here we engineer a two-dimensional periodic topographical design with detailed balance in its unit cell where we observe spontaneous particle edge guidance and corner accumulation of self-propelled particles.