Time-Dependent Multistate Switching of Topological Antiferromagnetic Order in Mn3Sn

Noncollinear antiferromagnets (AFMs) with topological electronic properties attract great interest, as they allow for all-electrical readout and manipulation of AFM order. The mechanisms and timescales to reverse AFM order are not known, though. In this study of current-driven switching of chiral AFM order in the classic Weyl semimetal Mn${}_{3}$Sn, time-resolved measurements show that switching is incoherent and occurs over several nanoseconds, owing to self-heating and then cooling of AFM domains in the presence of a Pt overlayer. These results unravel the spin dynamics of chiral AFMs and highlight the possibility of multilevel switching based on the temporal profile of current pulses.