Comunicazione
Orbitronics effects in spin-singlet superconductors.
Mercaldo M.T.
We consider a multi-orbital spin-singlet superconductor without inversion symmetry, $e.g.$, due to crystalline asymmetry as well as to electric fields or mechanical strain. The lack of inversion symmetry yields non-trivial orbital-Rashba couplings in the system that affect the electronic orbital texture at the surface leading to a dramatic impact on the superconductivity. We demonstrate that, by varying the strength of the orbital-Rashba couplings, the superconducting phase can be either suppressed, or undergo a $0-\pi$ transition, with the $\pi-phase$ being marked by non-trivial sign change of the superconducting order parameter between different bands. We have also studied the Edelstein effect, finding that the supercurrent-induced orbital magnetization is more than one order of magnitude greater than that due to the spin. Finally, in two-dimensional spin-singlet superconductors with low degree of spatial-symmetry content, we show that a vortex state at zero magnetic field can be energetically stable. The overall findings unveil a rich scenario to design heterostructures with superconducting orbitronics effects for the achievement, for instance, of all-electric superconducting devices.