Electronic states and persistent currents in rings with inhomogeneous Rashba spin–orbit coupling

The paper considers one-dimensional isolated quantum rings in a perpendicular magnetic field, in which Rashba spin-orbit coupling parameter changes along the ring. Electronic spectra and persistent currents of such ring structures are calculated for different values of the structure parameters and the magnitude of the magnetic flux. It is shown that the inhomogeneity of the Rashba parameter leads to anticrossing of energy levels and smoothing of the dependence of the persistent charge current on the flux. The influence of inhomogeneity on the spin persistent current turns out to be more significant: the projection of the spin current on the ring axis ceases to be preserved when moving along the ring; additional extrema or zeros appear on the dependence of the absolute value of the spin current on the magnetic flux for a given number of electrons in the ring.