Geometry tailored magneto-optical absorption spectra of elliptically deformed double quantum rings

ABSTRACT

We theoretically investigated the effect of the geometry change on the electronic and magneto-optical absorption spectra of GaAs/Ga_0.7Al_0.3As double quantum rings. The inner ring shape was changed continuously from circular to elliptic. Our numerical results revealed the decrement of the levels energies with the augments of the eccentricity of the internal/external ellipses that limit the inner ring, leading to a blue shift of the maxima in the absorption spectra in the magnetic field absence. Analysing separately the electronic spectra of the inner/outer single rings and of the double quantum rings structure in the magnetic field, we have found that, in the electronic spectra of the double ring, only the energies and the Aharonov–Bohm periodicity of the outer ring are altered by interference, while the Aharonov–Bohm oscillations of the inner ring levels propagate unchanged in the spectra. The magneto-optical spectra of elliptically deformed double quantum rings cover a wider range of energies than those of circular double ring and, at higher magnetic fields, present new peaks corresponding to transitions to higher states. Also, they show superposed peaks of increased absorption for a particular elliptic geometry and a red-shift of low energy maxima at the augment of the magnetic field which is the more pronounced the eccentricity increases. Moreover, the influence of the temperature is stronger than for the symmetrical structure.

KEYWORDS:

• Double quantum rings
• magnetic field
• absorption
• Aharonov–Bohm oscillations
• eccentricity

Disclosure statement

No potential conflict of interest was reported by the author(s).