Physics

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5 May 2021

The superconductivity and Lifshitz transition of Sr2RuO4 under uniaxial stress CANCELLED

Presented By Dr Clifford Hicks University of Birmingham, UK Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
  • 13:00-14:00

About this event

The superconductivity of Sr2RuO4, one of the most-studied materials in condensed matter physics, is known to be unconventional. There is evidence that it is in additional chiral, that is, that the superconducting condensate has a spontaneous angular momentum. In this talk, I will present results of studies under uniaxial stress. Under uniaxial stress, the Fermi surface structure of Sr2RuO4 is driven through a Lifshitz transition, that is, a change in topology. The superconductivity is strongly enhanced at this transition. I will present evidence from uniaxial pressure studies that the superconducting order parameter has even parity, and that it is likely to be chiral. This combination, however, leads to a conundrum: it points to a dxz ± idyz order parameter, which has a line node at kz=0. Horizontal line nodes are hard to understand in Sr2RuO4 because it is a layered compound with weak interlayer conduction.  The properties of superconducting Sr2RuO4 might be explainable only with a new pairing mechanism.