High sensitivity heat capacity measurements on Sr2RuO4 under uniaxial pressure

Abstract

A key question regarding the unconventional superconductivity of Sr${}_2$RuO${}_4$ remains whether the order parameter is single- or two-component. Under a hypothesis of two-component superconductivity, uniaxial pressure is expected to lift their degeneracy, resulting in a split transition. The most direct and fundamental probe of a split transition is heat capacity. Here, we report measurement of heat capacity of samples subject to large and highly homogeneous uniaxial pressure. We place an upper limit on the heat-capacity signature of any second transition of a few per cent of that of the primary superconducting transition. The normalized jump in heat capacity, $\Delta C/C$, grows smoothly as a function of uniaxial pressure, favouring order parameters which are allowed to maximize in the same part of the Brillouin zone as the well-studied van Hove singularity. Thanks to the high precision of our measurements, these findings place stringent constraints on theories of the superconductivity of Sr${}_2$RuO${}_4$.

This manuscript is an extended version of the scientific part of arXiv:1906.07597, which is being split into two separate papers. An extended discussion on the experimental methods can be found at arXiv:2009.03125. It includes supplemental material

References in corpus (8)

• High Resolution Polar Kerr Effect Measurements of Sr2RuO4: Evidence for Broken Time Reversal Symmetry in the Superconducting State
• Chiral P-Wave Order in Sr_2RuO_4
• The coherence-incoherence crossover and the mass-renormalization puzzles in Sr2RuO4
• Strong spin-orbit coupling effects on the Fermi surface of Sr2RuO4 and Sr2RhO4
• Hidden quasi one-dimensional superconductivity in Sr${}_2$RuO${}_4$
• Higher-Tc superconducting phase in Sr2RuO4 induced by uniaxial pressure
• Sharp magnetization jump at the first-order superconducting transition in Sr2RuO4
• Anisotropic Dependence of Superconductivity on Uniaxial Pressure in CeIrIn5

Cited by in corpus (7)

• Higher angular momentum pairings in interorbital shadowed-triplet superconductors: Application to Sr${}_2$RuO${}_4$
• Heat capacity double transitions in time-reversal symmetry broken superconductors
• Neutron scattering studies on spin fluctuations in Sr${}_2$RuO${}_4$
• $\mu$SR measurements on Sr${}_2$RuO${}_4$ under $⟨110⟩$ uniaxial stress
• Higher angular momentum pairing states in Sr${}_2$RuO${}_4$ in the presence of longer-range interactions
• A review of some new perspectives on the theory of superconducting Sr${}_2$RuO${}_4$
• Fingerprints of possible even-parity superconducting states in Sr${}_2$RuO${}_4$ detected by planar tunneling spectroscopy