Self-Consistent Calculation of the Electronic Structure and Electron–Electron Interaction in Self-Assembled InAs-GaAs Quantum Dot Structures

Abstract

Due to their small sizes, self-assembled quantum dots offer an excellent opportunity to study the physics of highly confined few-electron systems. This chapter addresses the electron-electron interaction within a single dot using a realistic structure with electron interactions treated within spin-density functional theory. The number of electrons in the dot is controlled by applying voltage to a metal gate on the top of the device. The strain tensor has been obtained from the minimization of the elastic energy of the system. The presence of the shear strains in the InAs-GaAs interfaces leads to the appearance of a polarization charge and its associated piezoelectric potential, which reduces the symmetry of the system, lifting some of the degeneracies observed in pyramidal quantum dot systems. The usual way of calculating the exchange energy of many-electron systems in the context of device physics is to use the local-density approximation of the Kohn-Sham density functional theory.