ORIGIN OF MAGIC ANGULAR-MOMENTUM IN A QUANTUM-DOT UNDER STRONG MAGNETIC-FIELD

This paper investigates origin of the extra stability associated with particular values (magic numbers) of the total angular momentum of ele ctrons in a quantum dot under strong magnetic field. The ground-state energy, distribution functions of density and angular momentum, and pa ir correlation function are calculated in the strong field limit by nu merical diagonalization of the system containing up to seven electrons . It is shown that the composite fermion picture explains the small ma gic numbers well, while a simple geometrical picture does better as th e magic number increases. Combination of these two pictures leads to i dentification of all the magic numbers. Relation of the magic-number s tates to the Wigner crystal and the fractional quantum Hall state is d iscussed.