Dresden 2020 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 41: Unconventional Superconductors
TT 41.6: Vortrag
Mittwoch, 18. März 2020, 16:30–16:45, HSZ 201
Direct observation of a uniaxial stress-driven Lifshitz transition in Sr2RuO4 — •Edgar Abarca Morales1,2, Veronika Sunko1,2, Igor Markovic1,2, Mark Barber1, Dijana Milosavjlevic1, Federico Mazzola2, Dmitry Sokolov1, Helge Rosner1, Clifford Hicks1, Philip King2, and Andrew Mackenzie1,2 — 1Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187, Dresden, Germany — 2SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, UK
Application of uniaxial pressure has recently been shown to more than double the transition temperature of the unconventional superconductor Sr2RuO4, leading to a peak in Tc versus strain whose origin is still under debate. Here we develop a simple and compact method to apply large uniaxial pressures in a way compatible with angle-resolved photoemission. We directly visualise how uniaxial stress drives a Lifshitz transition of the γ-band Fermi surface, pointing to the key role of strain-tuning its associated van Hove singularity to the Fermi level in mediating the peak in Tc. Our measurements provide stringent constraints for theoretical models of the strain-tuned electronic structure evolution of Sr2RuO4. Furthermore, our experimental approach opens the door to future studies of strain-tuned phase transitions where large pressure cells or piezoelectric-based devices may be difficult to implement.