Uniaxial strain-induced spin zero effect in ZrTe₅

We report uniaxial-strain control of spin interference in the Shubnikov–de Haas (SdH) oscillations of ZrTe₅. With increasing tensile strain along the crystallographic a axis, the SdH amplitude develops a pronounced node followed by a sign reversal of the oscillatory component, signaling a strain-tunable spin-zero condition. In contrast, the Landau fan intercept remains close to the value expected for a π Berry phase, indicating that the sign reversal is not caused by a global change in the Berry phase inferred from the fan diagram. We show that this behavior is captured by a strain-driven evolution of the relative phase between Zeeman-split cyclotron orbits. This evolution arises from the combined effects of strain-dependent splitting of the extremal Fermi-surface areas and an effective spin-dependent geometric phase in the Zeeman-split Dirac bands. Our results establish uniaxial strain as an in situ mechanical tuning parameter for accessing and traversing the spin-zero condition in topological quantum transport in ZrTe₅.