报告题目：Why the surface of Sr2RuO4 is not superconducting
摘要：
The superconducting order parameter of Sr2RuO4 still remains a puzzle after more than twenty years of research. One of the prime techniques for detecting the symmetry of a superconducting order parameter is quasi-particle interference imaging. Using QPI, not only the momentum structure, but also its phase can be detected. Surprisingly, despite its very two-dimensional electronic structure, evidence for the symmetry of the order parameter of Sr2RuO4 has remained inconclusive. I will review what we can learn from quasi-particle interference imaging about the surface electronic structure of Sr2RuO4 [1, 2], and show that from comparison of QPI and ARPES with continuum QPI calculations [2, 3], we can derive a microscopic model of the electronic structure of the surface layer. From this analysis, we understand the surface electronic structure with millielectronvolt precision. Using this knowledge, I will discuss how superconductivity is affected if we assume that pairing is mediated by electron correlations [4]. Our result show that if superconductivity in Sr2RuO4 is mediated by a correlation-driven mechanism, its order parameter is dx2-y2.
[1] Jonas B. Profe, Luke C. Rhodes, Matteo Dürrnagel, Rebecca Bisset, Carolina A. Marques, Shun Chi, Tilman Schwemmer, Ronny Thomale, Dante M. Kennes, Chris Hooley, and Peter Wahl, The magic angle of Sr2RuO4: optimizing correlation-driven superconductivity, arxiv/2405.14926.
[2] A. Chandrasekaran, L.C. Rhodes, E.A. Morales, C.A. Marques, P.D.C. King, P. Wahl, and J.J. Betouras, Engineering Higher Order Van Hove singularities in two dimensions: the example of the surface layer of Sr2RuO4, arxiv/2310.15331.
[3] A. Kreisel, C. A. Marques, L. C. Rhodes, X. Kong, T. Berlijn, R. Fittipaldi, V. Granata, A. Vecchione, P. Wahl, P.J. Hirschfeld, Quasiparticle Interference of the van-Hove singularity in Sr2RuO4, npj Quantum Materials 6, 100 (2021).
[4] Carolina A. Marques, Luke C. Rhodes, Rosalba Fittipaldi, Veronica Granata, Chi Ming Yim, Renato Buzio, Andrea Gerbi, Antonio Vecchione, Andreas W. Rost, Peter Wahl, Magnetic-field tunable intertwined checkerboard charge order and nematicity in the surface layer of Sr2RuO4, Adv. Mat. 33, 2100593 (2021).
简 历：
• >70 publications (3 in Nature and Science, 10 in other Nature and Science family journals, 8 in PRL), >4200 citations (Google Scholar (GS), Web of Science (WoS): >2700), 14 of the papers were cited more than 100 times (GS), 9 were selected as either Editor’s highlight, Editor’s suggestion or as cover image. h-index 29 (GS, WoS: 25)
• Independent Max-Planck-Research Group by Max Planck Society (September 2008)
• Feodor-Lynen-Fellowship of the Alexander-von-Humboldt Foundation (October 2006)
• Otto-Hahn-Medal of the Max-Planck-Society, Germany (June 2005)
• Nottingham Prize at the Physical Electronics Conference, Davis (CA), USA (June 2004)