Probing momentum-dependent scattering in uniaxially stressed Sr${}_2$RuO${}_4$ through the Hall effect

Abstract

Under in-plane uniaxial stress, the largest Fermi surface sheet of the correlated metal Sr${}_2$RuO${}_4$ undergoes a Lifshitz transition from an electron-like to an open geometry. We investigate the effects of this transition on transport through measurement of the longitudinal resistivity ${\rho }_{xx}$ and the Hall coefficient $R_{\text{H}}$. At temperatures where scattering is dominated by electron-electron scattering, $R_{\text{H}}$ becomes more negative across the Lifshitz transition, opposite to expectations from the change in Fermi surface topology. We show that this change in $R_{\text{H}}$ is explainable only if scattering changes throughout the Brillouin zone, not just at the point in $k$-space where the Lifshitz transition occurs. In a model of orbital-dependent scattering, the electron-electron scattering rate on sections of Fermi surface with $xy$ orbital weight decreases dramatically. On the other hand, at temperatures where defect scattering dominates ${\rho }_{xx}$ and $R_{\text{H}}$ are essentially constant across the Lifshitz transition.

9 pages, 10 figures