A device made of multilayer graphene exhibits topologically protected edge currents whose direction can be switched using an electric field.
Topological phases of matter have captivated physicists for several decades, promising exotic phenomena and new paradigms for electronic devices [1]. So-called Chern insulators—systems exhibiting quantized Hall conductance without an external magnetic field—are particularly enticing. These materials support dissipationless, one-way electron transport along their edges, which could enable robust low-power electronics or even form the backbone of future topological quantum-computing architectures [2]. Yet, the defining feature of a Chern insulator—its chirality, which determines the direction of the edge-state current—is set by material symmetry and is therefore notoriously rigid and difficult to manipulate dynamically [3–5].