Competing Nematicity and Fermi Liquid Behavior in Sr<sub>2</sub>RuO<sub>4</sub>
ORAL
Abstract
The normal state of the unconventional superconductor Sr2RuO4 (Tc = 1.45 K) is a textbook Fermi Liquid (FL), with signatures of long-lived quasiparticles seen in resistivity, optical conductivity and quantum oscillations below TFL∼30 K. However at higher temperatures, its resistivity increases unconstrained and eventually exceeds the Ioffe-Regel limit, indicative of strange metallic behavior. We present evidence from two experiments for the presence of nematic fluctuations (along [100]) in Sr2RuO4 above TFL. From ultrasound experiments, we find a large (∼20%) anomalous softening in the B1g shear modulus (c11 - c12)/2 between 300 K and 35 K, below which its behavior is standard. In contrast, the B2g shear modulus c66 shows standard behavior over the entire range. Motivated by this evidence of [100] nematicity, and to rule out a lattice origin of the effect, we then performed elastoresistivity measurements. We measure a diverging nematic susceptibility in the B1g channel which saturates around 60 K, about the same temperature where (c11 - c12)/2 starts to show deviations from Curie-Weiss behavior. Our study suggests that nematic correlations might be the reason behind non-FL physics in Sr2RuO4, and hints towards Sr2RuO4 being close to a nematic quantum critical point.
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Presenters
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Sayak Ghosh
- Cornell University