Correlation energies in the (1s-1p) triplet state of a two-electron spherical QD with square-well potential confinement are estimated for dots of different radii. The results are presented taking GaAs dot as an example. Our results show that the correlation energies are i) negative in a triplet state in contrast to the singlet state, ii)approaches zero as the dot size approaches infinity, and iii) the "fictitious crossing" of the singlet and triplet state energies at a particular dot size is explained on the basis of Hund's rules.
Spherical quantum dot; Square well confinement; Correlation energies; Singlet and Triplet states
