Technique for bulk Fermiology by photoemission applied to layered ruthenates

TL;DR

This paper uses bulk-sensitive high-energy photoemission to map the Fermi surfaces of layered ruthenates, revealing nesting instabilities and composition-dependent electron correlation effects, advancing understanding of their electronic structure.

Contribution

It introduces a technique for bulk Fermiology using photoemission, applied to layered ruthenates, providing direct Fermi surface measurements and insights into magnetic fluctuations.

Findings

Identified Fermi surface shapes in Sr2RuO4 and Sr1.8Ca0.2RuO4

Provided evidence for nesting instability and magnetic fluctuations

Showed electron correlation effects vary with composition

Abstract

We report the Fermi surfaces of the superconductor Sr2RuO4 and the non-superconductor Sr1.8Ca0.2RuO4 probed by bulk-sensitive high-energy angle-resolved photoemission. It is found that there is one square-shaped hole-like, one square-shaped electron-like and one circle-shaped electron-like Fermi surface in both compounds. These results provide direct evidence for nesting instability giving rise to magnetic fluctuations. Our study clarifies that the electron correlation effects are changed with composition depending on the individual band.