Half-quantum vortex andd̂-soliton inSr2RuO4

Assuming that the superconductivity in ${\mathrm{Sr}}_2{\mathrm{RuO}}_4$ is described by a planar p-wave order parameter, we consider possible topological defects in ${\mathrm{Sr}}_2{\mathrm{RuO}}_4.$ In particular, it is shown that both the $\mathrm{d̂}$-soliton and half-quantum vortex can be created in the presence of the magnetic field parallel to the $a-b$ plane. We discuss how one can detect the $\mathrm{d̂}$-soliton and half-quantum vortex experimentally.