Nonreciprocal Current in Noncentrosymmetric Rashba Superconductors

We study theoretically the nonreciprocal charge transport in two-dimensional noncentrosymmetric superconductors with the Rashba spin-orbit interaction. The resistivity R depends on the current I linearly under the external magnetic field B, i.e., R = R-0(1 + gamma BI), which is called the magnetochiral anisotropy. It is found that the coefficient gamma is gigantically enhanced by the superconducting fluctuation with the components of both spin singlet and triplet pairings, compared with that in the normal state. This finding offers a method to quantitatively estimate the ratio of the pairing interactions between the singlet and triplet channels including its sign.