Elastocaloric determination of the phase diagram of Sr2RuO4
Journal
Nature
Journal Volume
607
Journal Issue
7918
Start Page
276
End Page
280
ISSN
0028-0836
1476-4687
Date Issued
2022-07-13
Author(s)
Markus Garst
Jörg Schmalian
Sayak Ghosh
Naoki Kikugawa
Dmitry A. Sokolov
Clifford W. Hicks
Fabian Jerzembeck
Matthias S. Ikeda
Zhenhai Hu
B. J. Ramshaw
Andreas W. Rost
Michael Nicklas
Andrew P. Mackenzie
Abstract
One of the main developments in unconventional superconductivity in the past two decades has been the discovery that most unconventional superconductors form phase diagrams that also contain other strongly correlated states. Many systems of interest are therefore close to more than one instability, and tuning between the resultant ordered phases is the subject of intense research1. In recent years, uniaxial pressure applied using piezoelectric-based devices has been shown to be a particularly versatile new method of tuning2,3, leading to experiments that have advanced our understanding of the fascinating unconventional superconductor Sr2RuO4 (refs. 4–9). Here we map out its phase diagram using high-precision measurements of the elastocaloric effect in what we believe to be the first such study including both the normal and the superconducting states. We observe a strong entropy quench on entering the superconducting state, in excellent agreement with a model calculation for pairing at the Van Hove point, and obtain a quantitative estimate of the entropy change associated with entry to a magnetic state that is observed in proximity to the superconductivity. The phase diagram is intriguing both for its similarity to those seen in other families of unconventional superconductors and for extra features unique, so far, to Sr2RuO4.
Publisher
Springer Science and Business Media LLC
Type
journal article