SELF-CONSISTENT CALCULATION OF THE ELECTRONIC-STRUCTURE AND ELECTRON-ELECTRON INTERACTION IN SELF-ASSEMBLED INAS-GAAS QUANTUM-DOT STRUCTURES

We have performed a detailed self-consistent calculation of the electr onic structure and electron-electron interaction energy in pyramidal s elf-assembled InAs-GaAs quantum dot structures. Our model is general f or three-dimensional quantum devices without simplifying assumptions o n the shape of the confining potential nor fitting parameters. We have used a continuum model for the strain, from which the position-depend ent effective mass and band diagram are calculated. The number of elec trons in the dot is controlled by applying an external voltage to a me tal gate on the top of a complete multilayer device containing a singl e dot. In order to determine the electron occupation number in the dot that minimizes the total energy of the system, we have adopted the co ncept of transition state as defined by Slater for shell filling in at oms. We have calculated the exchange and correlation terms of the many -body Hamiltonian using the local (-spin) -density approximation. By a ccounting for spins we have been able to determine the shell structure in the pyramid and to calculate the energy differences between the va rious spin configurations. We have also calculated the different contr ibutions to the total electronic energy in the dot, i.e., the single-p article energies, the exchange-correlation energy, and the classical e lectrostatic electron-electron repulsion energy as a function of the g ate voltage and number of electrons in the dot. Comparison with recent experimental data of Fricke et al. [Europhys. Lett. 36, 197 (1996)] s hows good agreement. [S0163-1829(98)02008-6].