Aharonov-Bohm effect of excitons in nanorings - art. no. 195307

The magnetic field effects on excitons in an InAs nanoring are studied theo retically. By numerically diagonalizing the effective-mass Hamiltonian of t he problem that can be separated into terms in center-of-mass and relative coordinates, we calculate the low-lying excitonic energy levels and oscilla tor strengths as a function of the ring width and the strength of an extern al magnetic field. It is shown that in the presence of Coulomb correlation, the so-called Aharonov-Bohm effect of excitons exists in a finite (but sma ll) width nanoring. However, when the ring width becomes large, the non-sim ply-connected geometry of nanorings is destroyed, causing the suppression o f the Aharonov-Bohm effect. The analytical results are obtained for a narro w-width nanoring in which the radial motion is the fastest one and adiabati cally decoupled from the azimuthal motions. The conditional probability dis tribution calculated for the low-lying excitonic states allows identificati on of the presence of the Aharonov-Bohm effect. The linear optical suscepti bility is also calculated as a function of the magnetic field, to be compar ed with the future measurements of optical emission experiments on InAs nan orings.