Odd-parity superconductivity by competing spin-orbit coupling and orbital effect in artificial heterostructures

TL;DR

This paper demonstrates that odd-parity superconductivity can arise in multilayer Rashba systems through competing spin-orbit coupling and orbital effects, without the need for spin-triplet pairing, and identifies it as a topological state.

Contribution

It reveals a mechanism for odd-parity superconductivity in multilayer heterostructures driven by layer-dependent Rashba spin-orbit coupling and orbital effects, expanding understanding of topological superconductors.

Findings

Odd-parity PDW state is stabilized by spin-singlet pairing in multilayer systems.

The PDW state is a symmetry-protected topological superconductor with a one-dimensional winding number.

Potential realization in heavy-fermion superlattices and oxide interfaces.

Abstract

We show that odd-parity superconductivity occurs in multilayer Rashba systems without requiring spin-triplet Cooper pairs. A pairing interaction in the spin-singlet channel stabilizes the odd-parity pair-density-wave (PDW) state in the magnetic field parallel to the two-dimensional conducting plane. It is shown that the layer-dependent Rashba spin-orbit coupling and the orbital effect play essential roles for the PDW state in binary and tricolor heterostructures. We demonstrate that the odd-parity PDW state is a symmetry-protected topological superconducting state characterized by the one-dimensional winding number in the symmetry class BDI. The superconductivity in the artificial heavy-fermion superlattice CeCoIn_5/YbCoIn_5 and bilayer interface SrTiO_3/LaAlO_3 is discussed.