Journal Article

High-Resolution Photoemission on Sr2RuO4 Reveals Correlation-Enhanced Effective Spin-Orbit Coupling and Dominantly Local Self-Energies

Bruno, F Y, Tamai, A, Strand, H U R, Riccò, S, Radović, M, Meevasana, W, King, P D C, S. McKeown Walker, Shi, M, Cappelli, E, Baumberger, F, Rozbicki, E, Gibbs, A S, Mackenzie, A P, de la Torre, A, Plumb, N C, Georges, A, Berthod, C, Zingl, M, Kim, M

2019

Overview

We explore the interplay of electron-electron correlations and spin-orbit coupling in the model Fermi liquidSr2RuO4using laser-based angle-resolved photoemission spectroscopy. Our precise measurement of the Fermi surface confirms the importance of spin-orbit coupling in this material and reveals that its effective value is enhanced by a factor of about 2, due to electronic correlations. The self-energies for theβandγsheets are found to display significant angular dependence. By taking into account the multi-orbital composition of quasiparticle states, we determine self-energies associated with each orbital component directly from the experimental data. This analysis demonstrates that the perceived angular dependence does not imply momentum-dependent many-body effects but arises from a substantial orbital mixing induced by spin-orbit coupling. A comparison to single-site dynamical mean-field theory further supports the notion of dominantly local orbital self-energies and provides strong evidence for an electronic origin of the observed nonlinear frequency dependence of the self-energies, leading to “kinks” in the quasiparticle dispersion ofSr2RuO4.

• Publisher: American Physical Society
• Subject: Angular momentum / Correlation / Data analysis / Electron spin / Electron states / Elementary excitations / Fermi surfaces / Laser applications / Mean field theory / Momentum / Orbitals / Photoelectric emission / Spectrum analysis / Spin-orbit interactions / Strontium ruthenium oxide