Fig. 1: Electric current control of helicity in an itinerant longitudinal spiral magnet.

a Illustrations of chiralities of molecules and spiral magnets. γ = ± denotes the chirality (helicity). b Illustrations of the magnetic structure of spiral magnets in the presence of a magnetic field or electric current. In the presence of a magnetic field, the magnetic moments are tilted to the field direction, forming a conical magnetic structure. The net magnetization is along the magnetic field, irrespective of the chirality. The electric current along the propagation vector also induces the conical magnetic structure. In this case, the net magnetization direction is dependent on the chirality. c Illustrations of the electric current control of helicity in a longitudinal spiral magnet. The energetically favored helicity in the presence of magnetic field H and electric current j depends on whether they are parallel or antiparallel to each other.