Experiments reveal that quasiparticle properties in the superconductor Sr2RuO4 have a significant angular dependence due to the combined effects of local electron interactions and spin-orbit coupling.
We determine the variation of the mass enhancement along the entire Fermi surface, which shows a strong dependence on the direction of the quasiparticle momentum. This is often interpreted as a signature of nonlocal interactions that are strong at certain momenta and weak at others. However, using a new method to analyze our data, we show that this momentum dependence is apparent only if the problem is described in a momentum-space basis and disappears almost completely when electronic states are described in a basis of local orbitals.
This work is published in Phys. Rev. X.