Anomalous strain relaxation and light-hole character enhancement in GaAs capped InAs/In0.53Ga0.47As quantum ring

We theoretically investigated the strain profiles and the electronic structures of InAs/In0.53Ga0.47As quantum dot and GaAs capped quantum ring. In contrast to the intuitive expectation that the GaAs layer applies a strong compressive strain along the lateral directions of InAs, the GaAs embedded in the In0.53Ga0.47As matrix provides enough space for the InAs relaxation. The GaAs embedded in In0.53Ga0.47As acts as potential barrier for both electrons and heavy-holes, and as potential well for light-holes. Each hole state of the quantum ring exhibits two to eight times larger light-hole character than that of a quantum dot. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)