Order parameter in superconductors with nondegenerate bands

[摘要] In noncentrosymmetric metals, the spin degeneracy of the electronic bands is lifted by spin-orbit coupling. We consider general symmetry properties of the pairing function Delta(k) in noncentrosymmetric superconductors with spin-orbit coupling (NSC), including CePt3Si, UIr, and Cd2Re2O7. We find that Delta(k)=chi(k)t(k), where chi(k) is an even function which transforms according to the irreducible representations of the crystallographic point group and t(k) is a model-dependent phase factor. We consider tunneling between a NSC and a conventional superconductor. It is found that, in terms of thermodynamical properties as well as the Josephson effect, the state of NSC resembles a singlet superconducting state with gap function chi(k).

[发布日期] 2004-12-01

[关键词] PYROCHLORE OXIDE;SYMMETRY;CD2RE2O7;SESQUICARBIDE;CEPT3SI;SYSTEM