Current partition at topological channel intersections

An intersection between one-dimensional chiral channels functions as a topological current splitter. We find that the splitting of a chiral zero-line mode obeys very simple yet highly counterintuitive partition laws that relate current paths to the geometry of the intersection. Our results have far reaching implications for electron beam splitter and interferometer device proposals based on chiral transport, and for understanding transport in systems in which multiple topological domains lead to a statistical network of chiral channels.