Rigid-Band Shift of the Fermi Level in a Strongly Correlated Metal: Sr(2-y)La(y)RuO(4)

TL;DR

This study investigates how electron doping via La substitution in Sr2RuO4 causes a rigid shift of the Fermi level without changing quasiparticle mass, affecting susceptibility but not superconductivity.

Contribution

It demonstrates that La doping induces a rigid-band shift in Sr2RuO4 with minimal impact on quasiparticle mass and superconducting pairing, providing insight into electron doping effects in strongly correlated metals.

Findings

Fermi level shifts rigidly with doping

Quasiparticle mass enhancement remains constant

Superconducting pairing strength is unaffected

Abstract

We report a systematic study of electron doping of Sr2RuO4 by non-isovalent substitution of La^(3+) for Sr^(2+). Using a combination of de Haas-van Alphen oscillations, specific heat, and resistivity measurements, we show that electron doping leads to a rigid-band shift of the Fermi level corresponding to one doped electron per La ion, with constant many-body quasiparticle mass enhancement over the band mass. The susceptibility spectrum is substantially altered and enhanced by the doping but this has surprisingly little effect on the strength of the unconventional superconducting pairing.