High-sensitivity heat-capacity measurements on Sr2RuO4 under uniaxial pressure
Journal
Proceedings of the National Academy of Sciences
Journal Volume
118
Journal Issue
10
Start Page
e2020492118
ISSN
0027-8424
1091-6490
Date Issued
2021-03-02
Author(s)
Naoki Kikugawa
Dmitry A. Sokolov
Fabian Jerzembeck
Alexandra S. Gibbs
Yoshiteru Maeno
Clifford W. Hicks
Jörg Schmalian
Michael Nicklas
Andrew P. Mackenzie
Abstract
A key question regarding the unconventional superconductivity of Sr2RuO4 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 percent of that of the primary superconducting transition. The normalized jump in heat capacity, ∆C/C, grows smoothly as a function of uniaxial pressure, favoring 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 Sr2RuO4
Subjects
Heat capacity
Superconductivity
Uniaxial pressure
SDGs
Publisher
Proceedings of the National Academy of Sciences
Type
journal article