Low temperature magnetic penetration depth of a superconductor without inversion symmetry: Application to CePt3Si

The magnetic penetration depth of a superconductor without inversion symmetry by considering a Cooper pairing model with a two-component order parameter composed of spin-singlet and spin-triplet pairing components in the presence of nonlineary, nonlocality, and impurity effects is investigated. By using Green’s function method and linear response theory we calculate the appropriate correlation function to evaluate the magnetic penetration depth.For a noncentrosymmetric and clean superconductor such as CePt3Si a linear temperature dependence of the magnetic penetration depth at low temperatures, suggests that the gap function has line nodes, consistent with this gap model. We argue that nonlocal effects below the crossover temperature Tnonloc∗=0.015K, can explain the T2 dependence instead of the T-linear behavior expected for line nodes in this compound.In a dirty superconductor the quadratic temperature dependence of the magnetic penetration depth may come from either impurity scattering or nonlocality, but the nonlocality and nodal behavior may be hidden by the impurity effects.