Abstract
We investigate the order parameter of noncentrosymmetric superconductors and via the behavior of the penetration depth . The low-temperature penetration depth shows BCS-like behavior in , while in it follows a linear temperature dependence. We propose that broken inversion symmetry and the accompanying antisymmetric spin-orbit coupling, which admix spin-singlet and spin-triplet pairing, are responsible for this behavior. The triplet contribution is weak in , leading to a wholly open but anisotropic gap. The significantly larger spin-orbit coupling in allows the spin-triplet component to be larger in , producing line nodes in the energy gap as evidenced by the linear temperature dependence of . The experimental data are in quantitative agreement with theory.
- Received 20 December 2005
DOI:https://doi.org/10.1103/PhysRevLett.97.017006
©2006 American Physical Society