Measurement of Stress-Strain Relationships of Correlated Electron Systems

Abstract

In this article, we review recently developed piezoelectric-driven uniaxial stress apparatus, and associated methodology. The apparatus enables precise control of uniaxial stress, and measurement of samples’ stress-strain relationships. This technique not only facilitates well-calibrated uniaxial stress tuning experiments, but also serves as a thermodynamic probe of strain-induced changes in electronic structure. As a representative example, we highlight recent studies on the strongly correlated system Sr₂RuO₄, where measurement of stress-strain curves revealed a pronounced softening of the Young’s modulus with decreasing temperature near a Lifshitz transition, reflecting an increase in the entropy of the conduction electrons.