ENERGY SPACING IN CHARGING A QUANTUM-DOT - THE EFFECT OF THE ELECTRON-ELECTRON INTERACTIONS

Recent experiments on quantum dots have shown that by adding one elect ron at a time to a quantum dot the energy spacings 'are rather uniform and decrease slightly' as the number of electrons increases (Ashoori et nl 1993 Phys. Rev. Lett. 71 613). By applying the scaled Kohn-Sham equations to a cylindrical quantum dot system we show that this is due to the effect of the electron-electron interactions. The interactions , especially the Coulomb interaction, cause a significant redistributi on of the electronic charge density which is determined by the effect of the boundary condition of the quantum dot in minimizing the total e nergy of the system. To ensure that the effect of the electron-electro n interactions is independent of the specific potential used in defini ng the quantum dot, two model potentials (a constant potential and a p otential that is harmonic in the radial part) are considered.