Probing Momentum-Dependent Scattering in Uniaxially Stressed Sr₂RuO₄ through the Hall Effect

The largest Fermi surface sheet of the correlated metal Sr₂RuO₄ can be driven through a Lifshitz transition between an electronlike and an open geometry by uniaxial stress applied along the [100] lattice direction. Here, we investigate the effect of this transition on the longitudinal resistivity ρ_xx and the Hall coefficient R_H. ρ_xx(T), when Sr₂RuO₄ is tuned to this transition, is found to have a T² log T form, as expected for a Fermi liquid tuned to a Lifshitz transition. R_H is found to become more negative as the Fermi surface transitions from an electronlike to an open geometry, opposite to general expectations from this change in topology. The magnitude of the change in RH implies that scattering changes throughout the Brillouin zone, not just at the point in k space where the transition occurs. In a model of orbital-dependent scattering, the electron-electron scattering rate on sections of Fermi surface with xy orbital weight is found to decrease dramatically.