Dynamical superconducting order parameter domains in Sr2RuO4

• Published in: Science (American Association for the Advancement of Science) 2006-11, Vol.314 (5803), p.1267-1271
• Main Authors: KIDWINGIRA, Francoise, STRAND, J. D, VAN HARLINGEN, D. J, MAENO, Yoshiteru
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Crystals; Exact sciences and technology; Magnetic fields; Metals, alloys and compounds (a15, 001c15, laves phases, chevrel phases, borocarbides, etc.); Physics; Proximity effects, weak links, tunneling phenomena, and josephson effects, adreev effect, sn and sns junctions; Superconducting materials (excluding high-tc compounds); Superconductivity; Superconductors
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1133239

We present direct evidence for complex p-wave order parameter symmetry and the presence of dynamical chiral order parameter domains of the form px +/- ipy in the ruthenate superconductor Sr2RuO4. The domain structure creates differences in the magnetic field modulation of the critical current of Josephson junctions fabricated on orthogonal faces of Sr2RuO4 single crystals. Transitions between the chiral states of a domain or the motion of domain walls separating them generates telegraph noise in the critical current as a function of magnetic field or time and is responsible for hysteresis observed in field sweeps of the critical current. The presence of such domains confirms the p-wave triplet spin and complex (broken time-reversal symmetry) nature of the superconducting pairing state in Sr2RuO4.