Multi-component order parameter superconductivity of Sr${}_2$RuO${}_4$ revealed by topological junctions

Abstract

Single crystals of the Sr${}_2$RuO${}_4$-Ru eutectic system are known to exhibit enhanced superconductivity at 3~K, in addition to the bulk superconductivity of Sr${}_2$RuO${}_4$ at 1.5~K. The 1.5-K phase is believed to be a spin-triplet, chiral $p$-wave state with the multi-component order parameter, giving rise to chiral domain structure. In contrast, the 3-K phase is attributable to enhanced superconductivity of Sr${}_2$RuO${}_4$ in the strained interface region between Ru inclusion of a few to tens of micrometers in size and the surrounding Sr${}_2$RuO${}_4$. We investigate the dynamic behavior of a topological junction, where a superconductor is surrounded by another superconductor. Specifically, we fabricated Nb/Ru/Sr${}_2$RuO${}_4$ topological superconducting junctions, in which the difference in phase winding between the $s$-wave superconductivity in Ru micro-islands induced from Nb and the superconductivity of Sr${}_2$RuO${}_4$ mainly governs the junction behavior. Comparative results of the asymmetry, hysteresis and noise in junctions with different sizes, shapes, and configurations of Ru inclusions are explained by the chiral domain-wall motion in these topological junctions. Furthermore, a striking difference between the 1.5-K and 3-K phases is clearly revealed: the large noise in the 1.5-K phase sharply disappears in the 3-K phase. These results confirm the multi-component order-parameter superconductivity of the bulk Sr${}_2$RuO${}_4$, consistent with the chiral $p$-wave state, and the proposed non-chiral single-component superconductivity of the 3-K phase.

References in corpus (9)

• High Resolution Polar Kerr Effect Measurements of Sr2RuO4: Evidence for Broken Time Reversal Symmetry in the Superconducting State
• Strong Peak in $T_c$ of Sr${}_2$RuO${}_4$ Under Uniaxial Pressure
• First-Order Superconducting Transition of Sr2RuO4
• Vertical line nodes in the superconducting gap structure of Sr2RuO4
• Direct penetration of spin-triplet superconductivity into a ferromagnet in Au/SrRuO3/Sr2RuO4 junctions
• Anomalous Transport through the p-Wave Superconducting Channel in the 3-K Phase of Sr2RuO4
• Higher-Tc Superconducting Phase in Sr2RuO4 Induced by In-Plane Uniaxial Pressure
• Absence of ${}^{17}$O Knight-Shift Changes across the First-Order Phase Transition Line in Sr${}_2$RuO${}_4$
• Limiting mechanism for critical current in topologically frustrated Josephson junctions

Cited by in corpus (16)

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• Time-Reversal Invariant Superconductivity of Sr${}_2$RuO${}_4$ Revealed by Josephson Effects
• Little-Parks oscillations with half-quantum fluxoid features in Sr2RuO4 micro rings
• Possible three-dimensional nematic odd-parity superconductivity in Sr${}_2$RuO${}_4$
• Spontaneous emergence of Josephson junctions in homogeneous rings of single-crystal Sr2RuO4
• Spontaneous superconducting diode effect in non-magnetic Nb/Ru/Sr${}_2$RuO${}_4$ topological junctions
• Constraints on the superconducting state of Sr${}_2$RuO${}_4$ from elastocaloric measurements
• A microscopic Ginzburg--Landau theory and singlet ordering in Sr${}_2$RuO${}_4$
• Degeneracy between even- and odd-parity superconductivity in the quasi-1D Hubbard model and implications for Sr2RuO4
• Observation of superconducting gap spectra of long-range proximity effect in Au/SrTiO${}_3$/SrRuO${}_3$/Sr${}_2$RuO${}_4$ tunnel junctions
• Josephson current between two $p$-wave superconducting nanowires in the presence of Rashba spin-orbit interaction and Zeeman magnetic fields
• A Review of Electronic Transport in Superconducting Sr${}_2$RuO${}_4$ Junctions
• Half-quantum vortices on c-axis domain walls in chiral p-wave superconductors
• Anomalous anisotropic behaviour of spin-triplet proximity effect in Au/SrRuO${}_3$/Sr${}_2$RuO${}_4$ junctions
• DC-current induced domain wall in a chiral $p$-wave superconductor
• Josephson effects in the spin-triplet superconductor/altermagnet/spin-triplet superconductor junctions: the detection of the intrinsic $\mathbf{d}$-vector