Electron Correlation and Pairing States in Superconductors without Inversion Symmetry

This article is a pedagogical review of theoretical studies of noncentrosymmetric superconductors with particular emphasis on the role played by electron correlation, which is important for heavy fermion systems. We survey unique properties of parity-violated superconductivity such as the admixture of spin singlet and triplet states, unusual paramagnetism, large Pauli limiting fields, magnetoelectric effects, the helical vortex phase, and the anomalous Hall effect. It is pointed out that these remarkable features are strengthened by a strong electron correlation effect, and thus are prominent in heavy fermion superconductors without inversion symmetry. We also discuss possible pairing states realized in the heavy fermion system CePt$_3$Si.