Aharonov-Bohm nanoring with periodically modulated Rashba interaction: Energy spectrum and persistent currents

Abstract

Energy spectra and persistent currents in one-dimensional quantum rings with inhomogeneous spin-orbit Rashba interaction (RSOI) in the presence of Aharonov-Bohm magnetic flux are studied. It is shown that suppression of RSOI in some part of the ring leads to the level anticrossing which results in smoothing the magnetic flux dependence of the charge persistent current. For a periodic ring structure with alternating RSOI and non-RSOI segments the energy levels are grouped into gap-separated subbands. The flux dependence of the charge persistent current of such a ring has a sawtooth shape (as for a ring with uniform RSOI) except for the case of complete filling of several subbands by electrons, where the dependence becomes smooth. We also calculated the persistent spin current. It was shown that the angular dependence of its density satisfies certain symmetry conditions, which are determined by the structure period and the angular width of its non-RSOI part.