Multi-domain electromagnetic absorption of triangular quantum rings

We present a theoretical study of the electron energy structure, carrier localization and optical absorption of triangular core-shell quantum rings. We show how those features can be established during the manufacturing process through the sample diameter, side thickness and, to higher extend, by an external magnetic field. In particular, we show that the energy levels are shifted to lower values and the energy splitting between the two lowest levels increases while the energy gap separating corner-localized from side-localized states strongly decreases in the case of narrow rings and slightly increases for very thick samples. The result is a thickness dependent absorption spectrum where one transition may be tuned in the THz domain and a second transition can be tuned from THz to the infrared range of electromagnetic spectrum.