Suppression of the Aharonov-Bohm effect in hexagonal quantum rings

Abstract

Few-electron states of AlAs-GaAs-AlAs hexagonal quantum rings pierced by an axial magnetic field are computed through full configuration interaction calculations. The quantum ring is in the low-density regime, populated with N = 1 up to N = 7 electrons. Similar to circular rings, the energy spectra of the hexagonal ones reflect an integer and fractional Aharonov-Bohm regular oscillation pattern for N = 1 and , respectively. Deviations from the regular fractional period with increasing electron density become apparent for larger N. Remarkably, for N = 6 the Aharonov-Bohm effect is completely suppressed. This is a unique symmetry-related feature of hexagonal rings that only can emerge in the low-density regime.