Many-body interference in kagome crystals.

Abstract

When electrons in metals act collectively, they enable emergent phenomena and electronic functionalities that transcend the behaviour of individual particles¹. Coherent collective charge motion has so far been observed primarily in superconductors, in which it arises with the formation of Cooper pairs^2,3. Here we report experimental evidence for coherent charge transport in the normal state of the kagome metal CsV₃Sb₅, indicative of a distinct collective electronic state. The signature is a set of magnetoresistance oscillations in mesoscopic crystalline pillars under in-plane magnetic fields, with a periodicity determined by the number of magnetic flux quanta h/e threading between adjacent kagome layers-effectively forming an interlayer Aharonov-Bohm interferometer. The cooperative nature of this phenomenon is evidenced by a non-analytic angular dependence characterized by abrupt transitions between discrete oscillation frequencies and its persistence over length scales that exceed the single-particle mean free path. Notably, the oscillation amplitude matches other anomalous electronic responses reported in CsV₃Sb₅, pointing to an underlying mechanism that establishes intrinsic coherence. These findings shed new light on the debated nature of correlated order in kagome metals and establish CsV₃Sb₅ as a platform for realizing long-range coherent charge transport in the absence of superconductivity-opening new directions for coherence in correlated electron systems beyond conventional models.