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arXiv · 2002.02856

Reduction of the spin susceptibility in the superconducting state of Sr2RuO4 observed by polarized neutron scattering

A. N. Petsch·M. Zhu·Mechthild Enderle·Z. Q. Mao·Y. Maeno·I. I. Mazin·S. M. Hayden
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Abstract

Recent observations [A.~Pustogow et al. Nature 574, 72 (2019)] of a drop of the $^{17}$O nuclear magnetic resonance (NMR) Knight shift in the superconducting state of Sr$_2$RuO$_4$ challenged the popular picture of a chiral odd-parity paired state in this compound. Here we use polarized neutron scattering to show that there is a $34 \pm 6$ % drop in the magnetic susceptibility at the ruthenium site below the superconducting transition temperature. Measurements are made at lower fields $H \sim \tfrac{1}{3} H_{c2}$ than a previous study allowing the suppression to be observed. Our results are consistent with the recent NMR observations and rule out the chiral odd-parity $\mathbf{d}=\hat{\mathbf{z}}(k_x\pm ik_y)$ state. The observed susceptibility is consistent with several recent proposals including even-parity $B_{1g}$ and odd-parity helical states.

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A. N. Petsch, M. Zhu, Mechthild Enderle, Z. Q. Mao, Y. Maeno, I. I. Mazin, S. M. Hayden. 2020-02-07. Reduction of the spin susceptibility in the superconducting state of Sr2RuO4 observed by polarized neutron scattering. https://doi.org/10.1103/physrevlett.125.217004

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