Influence of chiral surface states on the London penetration depth in Sr2RuO4

The London penetration depth for the unconventional superconductor Sr2RuO4 is analyzed assuming an order parameter which breaks time-reversal symmetry and parity simultaneously. Such a superconductor possesses gapless chiral quasiparticle states at the surface. We show that these subgap states contr ibute significantly to the low-temperature behavior of the London penetrati on depth, yielding a T-2 power law even though bulk quasiparticle spectrum is gapped. The presence of several electron bands gives rise to interband t ransition among the subgap surface states and influences the properties of the surface impedance. The surface states also lead to a nonlinear Meissner effect.