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Abstract

AP470

Thursday, 6 June 2019 at 3:15 pm

McCullough, First Floor Auditorium, Room #115

 

Host: Steve Kivelson

 

Stuart Brown

University of California, Los Angeles

 

17O NMR probe of the unconventional superconductivity in strained Sr2RuO4

The quasi-two-dimensional Sr2RuO4 has long been considered a solid state analog to the archetypal Fermi Liquid 3He, with strong normal state correlations, and odd-parity superconductivity in the ground state that also breaks time reversal symmetry. A split superconducting transition is expected under conditions of in-plane strain along [100], since the distortion removes the degeneracy of the proposed two-component order parameter. Instead, a strong peak in Tc was observed. This and other puzzles motivated our study of the normal and superconducting states using 17O NMR under stressed conditions. The normal state Knight shifts are consistent with tuning EF through a van Hove singularity, along with an associated Stoner factor enhancement. A reduced spin polarization is observed in the superconducting state for all strains, eliminating the chiral p-wave state as a possible superconducting order parameter.