Magnetoexcitons in quantum-ring structures: a novel magnetic interference effect

A novel magnetic interference effect is proposed for a neutral, but polarizable exciton in a quantum ring with a finite width. The magnetic interference effect originates from the nonzero dipole moment in the exciton. The ground state of exciton acquires a nonzero angular momentum with increasing normal magnetic field. This leads to the suppression of the photoluminescence in defined windows of the magnetic field. When a quantum particle moves along a closed trajectory in external electric and magnetic fields, the Aharonov-Bohm and Aharonov-Casher effects can occur, caused by quantum interference between paths with different phases. As is well known, the Aharonov-Bohm (AB) effect is related to a charged particle trajectory enclosing a magnetic flux. Here we present a novel magnetic interference effect for a neutral, but polarizable quasi-particle. In particular, we show here theoretically that the wave function of a neutral polarizable exciton acquires a nonzero phase when it moves in a quantum ring pierced by a magnetic flux. The neutral exciton wave function becomes sensitive to the magnetic flux because of a net radial electric-dipole moment induced by asymmetries in the nanostructure potential. The transition to a