Tuning the Fermi Liquid Crossover in Sr$_2$RuO$_4$ with Uniaxial Stress

TL;DR

This study investigates how uniaxial stress influences the Fermi liquid behavior in Sr$_2$RuO$_4$, revealing that strain can tune the coherence scale and approach a Lifshitz transition, supported by NMR measurements and theoretical modeling.

Contribution

The paper demonstrates the tunability of the Fermi liquid crossover in Sr$_2$RuO$_4$ using uniaxial stress, combining experimental NMR data with density-functional theory calculations.

Findings

Strain significantly alters the magnetic response of Sr$_2$RuO$_4$.

The Fermi liquid coherence scale decreases as the Lifshitz transition is approached.

A van-Hove singularity plays a key role in the observed phenomena.

Abstract

We perform nuclear magnetic resonance (NMR) measurements of the oxygen-17 Knight shifts for Sr$_2$RuO$_4$, while subjected to uniaxial stress applied along [100] direction. The resulting strain is associated with a strong variation of the temperature and magnetic field dependence of the inferred magnetic response. A quasi-particle description based on density-functional theory calculations, supplemented by many-body renormalizations, is found to reproduce our experimental results, and highlights the key role of a van-Hove singularity. The Fermi liquid coherence scale is shown to be tunable by strain, and driven to low values as the associated Lifshitz transition is approached.