Nonreciprocal current in noncentrosymmetric Rashba superconductors

• Published in: arXiv.org
• Main Authors: Wakatsuki, Ryohei, Nagaosa, Naoto
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 06.12.2017
• Subjects: Anisotropy; Dependence; Ferroelectric materials; Ferroelectricity; Magnetic fields; Order parameters; Parity; Physics - Superconductivity; Spin-orbit interactions; Superconductors; Symmetry; Transport phenomena; Variations
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1712.02086

Noncentrosymmetric superconductors with broken inversion symmetry \(P\) offer rich physical phenomena such as the upper critical magnetic field \(H_{c2}\) beyond the Pauli limit and magnetoelectric effect. The relativistic spin-orbit interaction (SOI) plays an essential role in these novel phenomena, which lifts the Kramers degeneracy at each \(\mathbf{k}\)-point, and leads to the mixing of the spin singlet-even parity and spin triplet odd-parity parings. On the other hand, the time-reversal symmetry \(T\) relates the two states at \(\mathbf{k}\) and \(-\mathbf{k}\) points with the opposite spins, and the external magnetic field \(B\) further breaking \(T\) leads to the directional dependence of the nonlinear resistivity called magnetochiral anisotropy (MCA). Here we demonstrate theoretically that the two-component nature of the order parameter, i.e., even and odd pairings, leads to the gigantic enhancement of the MCA in the fluctuation region, in Rashba superconductor as a representative example of noncentrosymmetric system. This reveals the superconducting analogue of "ferroelectric" appearing in the transport phenomena.