Field-tuned chiral transport in charge-ordered Kagome metal CsV₃Sb₅

When electric conductors differ from their mirror image, unusual chiral transport coefficients appear that are forbidden in achiral metals, such as a non-linear electric response known as electronic magneto-chiral anisotropy (eMChA). While chiral transport signatures are by symmetry allowed in many conductors without a center of inversion, it reaches appreciable levels only in rare cases when an exceptionally strong chiral coupling to the itinerant electrons is present. So far, observations of chiral transport have been limited to materials in which the atomic positions strongly break mirror symmetries. Here, we discuss chiral transport in the centro-symmetric layered Kagome metal CsV₃Sb₅, observed via second harmonic generation under in-plane magnetic field. The eMChA signal becomes significant only at temperatures below 35 K, deep within its charge-ordered state at 94 K. This temperature dependence reveals a direct correspondence between electronic chirality and unidirectional charge order, and field-tunability would be a natural consequence of spontaneous time-reversal-symmetry breaking. We show that the chirality is set by the out-of-plane field component and that a transition from left- to right-handed transport can be induced by changing the field sign. CsV₃Sb₅ is the first material in which strong chiral transport can be controlled and switched by small magnetic-field changes, in stark contrast to structurally chiral materials – a prerequisite for their application in electronics.