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TT: Fachverband Tiefe Temperaturen
TT 67: Unconventional Superconductors
TT 67.1: Invited Talk
Thursday, March 21, 2024, 09:30–10:00, H 3007
Giant lattice softening at a uniaxial-pressure-tuned Lifshitz transition in the unconventional superconductor Sr2RuO4 — •Hilary M. L. Noad — Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
In the unconventional superconductor Sr2RuO4, properties such as the transition temperature, the upper critical field, and the in-plane normal-state resistivity depend strongly on uniaxial pressure along the [100] direction. Underlying this behaviour is a pressure-tuned Lifshitz transition, at which there is a change in topology of one of the three quasi-two-dimensional Fermi surfaces. We investigated the influence of this electronic transition on the lattice by using a piezo-based uniaxial pressure cell to measure the stress-strain relation of Sr2RuO4 across the Lifshitz transition, revealing a large and strongly temperature dependent softening of the [100] Young’s modulus at the Lifshitz transition [1]. Through thermodynamic considerations and comparison to a tight-binding model, we show that the softening is indeed driven by conduction electrons. Moreover, the model describing this effect exhibits quantum critical elasticity, raising intriguing questions about the relationship between the superconductivity of Sr2RuO4 and the electronically driven softening of the lattice.
[1] H.M.L. Noad, K. Ishida, Y.-S. Li, E. Gati, V. Stangier, N. Kikugawa, D.A. Sokolov, M. Nicklas, B. Kim, I.I. Mazin, M. Garst, J. Schmalian, A.P. Mackenzie, C.W. Hicks, Science 382 (2023) 447.
Keywords: Lifshitz transition; Uniaxial pressure; Elasticity