Superconductivity in materials lacking inversion symmetry has been a topic of intense theoretical and experimental interest due to the unique effects of spin-orbit coupling on electronic bands. Spin splitting corroborated with magnetic/exchange field can lead to novel pairing states, such as the helical phase, characterized by Cooper pairs with finite center-of-mass momentum. This property gives rise to intriguing magneto-electric and magneto-chiral effects, including the enhancement of critical temperature in magnetic fields, supercurrent diode effects, and anomalous Josephson phenomena. In recent years, synthetic superconductors, such as two-dimensional electron gases with strong Rashba spin-orbit coupling have provided a platform to explore these phenomena and search for topological superconducting states. This talk will present an overview of non-centrosymmetric superconductivity, covering main theoretical concepts and key experimental observations, including: Supercurrent diode effect and Josephson inductance anisotropy in InAs-quantum well-based junctions [1], zero-pi-like transitions and anomalous Josephson effect in non-centrosymmetric systems [2], enhanced vortex pinning and squeezing in Rashba-based superconductors [3]. These phenomena are attributed to the Lifshitz invariant [4] in the Ginzburg-Landau free energy, which arises from the finite center-of-mass momentum of Cooper pairs.

References

[1] C. Baumgartner et al., Nature Nanotechnology 17 (1), 39 (2022)

[2] A. Costa et al., Nature Nanotechnology 18 (11), 1266 (2023)

[3] L. Fuchs et al., Physical Review X 12 (4), 041020 (2022)

[4] D. Kochan et al., arXiv:2303.11975