Dynamical Superconducting Order Parameter Domains in Sr2RuO4
Francoise Kidwingira,1
J. D. Strand,1
D. J. Van Harlingen,1*
Yoshiteru Maeno2
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
Sr
2RuO
4. The domain structure creates differences in the magnetic
field modulation of the critical current of Josephson junctions
fabricated on orthogonal faces of Sr
2RuO
4 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 Sr
2RuO
4.
2 Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
* To whom correspondence should be addressed. E-mail: dvh{at}uiuc.edu
