Title 



Exciton states in a nanocup in the presence of a perpendicular magnetic field


Author 





Abstract 



The exciton states in a strained (In,Ga)As/GaAs nanocup are theoretically determined. We explore how the nanocup bottom thickness (t) affects the magnetic field dependence of the exciton energy. Strain distribution is computed by the continuum mechanical model under the approximation of isotropic elasticity. The exciton wave functions are expanded into products of the electron and hole envelope functions. For small t, the exciton ground state has zero orbital momentum and exhibits small oscillations of the second derivative when the magnetic field increases. When t approaches the value of the cup height, however, the exciton levels exhibit angular momentum transitions, whose behavior is similar to that for typeII quantum dots. Small oscillations of the oscillator strength for exciton recombination are found when the magnetic field increases. An increase in thickness of the nanocup bottom has only a small effect on those oscillations for the optically active exciton states, but the exciton ground state becomes dark when the magnetic field increases. Hence, the results of our calculations show that an increase in thickness of the nanocup bottom transforms the exciton ground energy level dependence on magnetic field from the one characteristic of typeI rings to the one characteristic of typeII dots.  

Language 



English


Source (journal) 



Physica scripta.  Stockholm 

Publication 



Stockholm : 2012


ISSN 



00318949


Volume/pages 



T149(2012), p. 014054,1014054,5


Article Reference 



014054


ISI 



000303523500055


Medium 



Eonly publicatie


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