Horizontal Line Nodes in Sr2RuO4 Proved by Spin Resonance

Abstract

We investigated the low-energy incommensurate (IC) magnetic fluctuations in Sr${}_2$RuO${}_4$ by the high-resolution inelastic neutron scattering measurements and random phase approximation (RPA) calculations. We observed a spin resonance with energy of $\hslash {\omega }_{\text{res}}=0.56$~meV centered at a characteristic wavevector ${\mathbf{Q}}_{\text{res}}=(0.3,0.3,0.5)$. The resonance energy corresponds well to the superconducting gap $2\Delta =0.56$~meV estimated by the tunneling spectroscopy. The spin resonance shows the $L$ modulation with a maximum at around $L=0.5$. The $L$ modulated intensity of the spin resonance and our RPA calculations indicate that the superconducting gaps regarding the quasi-one-dimensional $\alpha$ and $\beta$ sheets at the Fermi surfaces have the horizontal line nodes. These results may set a strong constraint on the pairing symmetry of Sr${}_2$RuO${}_4$. We also discuss the implications on possible superconducting order parameters.

arXiv admin note: substantial text overlap with arXiv:1904.01234

References in corpus (6)

• High Resolution Polar Kerr Effect Measurements of Sr2RuO4: Evidence for Broken Time Reversal Symmetry in the Superconducting State
• First-Order Superconducting Transition of Sr2RuO4
• Sharp magnetization jump at the first-order superconducting transition in Sr2RuO4
• Nodeless spin triplet superconducting gap in Sr2RuO4
• Pauli-paramagnetic effects on mixed state properties in a strongly anisotropic superconductor ---Application to Sr_2_RuO_4_---
• Theoretical studies for identifying horizontal line nodes via angle-resolved density of states measurements ---Application to Sr${}_2$RuO${}_4$---

Cited by in corpus (2)

• Neutron scattering studies on spin fluctuations in Sr${}_2$RuO${}_4$
• Spin Fluctuations in Sr${}_{1.8}$La${}_{0.2}$RuO${}_4$