Effect of bipartition on spectral properties of nanorings

The effects of a special topological transformation on the energy levels, far-infrared spectra and magnetization of one electron inside a semiconductor nanoring under magnetic fields are studied. We have called this transformation as bipartition, and it is defined by a change in ring topological structure, when its shape is changed successively from a single oval-shaped loop up to quasi-two disconnected loops. Our results show that in the course of such transformation the low-lying energies dependencies with multiple crossovers between them, typical for the free electron rotation along an almost circular loop, are converted into a set of non-crossing double plaits related to a sub-barrier electron tunneling along a strongly non-circular loop in a quasi-local state. Also, we find that during the restructuring of the oval-shaped nanostructures the selection rules for the dipole transitions are changed allowing the appearance of additional peaks in the FIR spectrum.