Optical Detection of the Aharonov-Bohm Effect on a Charged Particle in a Nanoscale Quantum Ring

We study spectroscopically the current produced by a charged particle moving in a nanosize semiconductor quantum ring subject to a perpendicular magnetic field. Several Aharonov-Bohm oscillations are observed in the emission of a charged exciton confined in a single ring structure. The magnetic field period of the oscillations correlates well with the size of the rings.

Figure 1

(a) Electron micrograph of an ${\mathrm{I}\mathrm{n}}_{0.10}{\mathrm{G}\mathrm{a}}_{0.90}\mathrm{A}\mathrm{s}/\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}$ quantum ring. On top, the metallic mask produced by lithography before etching is seen. (b) Circularly polarized photoluminescence spectra of a single ring with an average radius $R_0$ of 33 nm for different magnetic fields.

Figure 2

Contour plot of the spectra shown in Fig. 1.

Figure 3

(a) Measured photon energy from charged exciton recombination (the symbols) plotted against magnetic field after subtracting a fit to the data using a quadratic form. The solid line shows the oscillation of an electron’s energy. (b) Calculated negative electron energy (dotted line), energy of two relative particles (dashed line), total energy of the $X^{-}$ complex (dash-dotted line), and photon energy (solid line).

Figure 4

(a) Magnetic field period of AB oscillations plotted versus tilt angle, as sketched in the inset. (b) Same as (a) but as function of average ring radius. Symbols give experimental data, lines theoretical expectations.