Apparent Phototaxis Enabled by Brownian Motion

Biomimetic behaviour in artificially created active matter that allow deterministic and controlled motility has become of growing interest in recent years. It is well known that phototrophic bacteria optimize their position with respect to light by phototaxis. Here, we describe how our magnetic, photocatalytic microswimmers apparently undergo phototactic behaviour. Since there is no obvious reason for the particles to do so, we analyze different influences and elucidate through experiments and theoretical considerations from which physical circumstances this behaviour originates.