Speaker
Description
My work is focussed on one of the most compelling unconventional superconductors to date, Strontium Ruthenate ($Sr_2RuO_4$). It has become a benchmark for experimentation and theoretical analysis because its normal-state electronic structure is known with exceptional precision, and because of experimental evidence that its superconductivity breaks time-reversal symmetry (TRS)i.e. chiral. Measurements under uniaxial strain offer an ideal way to test for chirality because under uniaxial strain the superconducting and chiral transitions are predicted to split, allowing the empirical signatures of each to be identified separately.
By combining Muon spin relaxation (which is a unique tool to study structural and dynamical processes that are taking place in the bulk of a material in an atomic scale) and the application of uniaxial strain (which is a good way to perturb a material without introducing any disorder) I am searching for conclusive evidence regarding the superconducting order parameter of $Sr_2RuO_4$. For this purpose, we developed a uniaxial strain device1 that is expected to widen the range of applications of the Muon spin relaxation method. Using this device, we observed a large strain-induced splitting between the onset temperatures of superconductivity and TRSB in $Sr_2RuO_4$. Moreover, at high strain beyond the van Hove singularity, a new spin density wave ordered phase is observed2.
[1 ] C. Hicks et al. Piezoelectric-Driven Uniaxial Stress Apparatus for Muon Spin Rotation. JPS Conf. Proc. 21, 011040 (2018)
[2 ]V. Grinenko, S. Ghosh et al, Split superconducting and time-reversal symmetry-breaking transitions and magnetic order in $Sr_2RuO_4$ under uniaxial stress. arXiv:2001.08152
