Quantum dots and quantum dot lattices: Correlations in small quantal systems

Recently, Attaccalite et al. proposed a new expression for the exchange-correlation energy of the two-dimensional electron gas, based on quantum Monte Carlo calculations. We compare this functional with the established expression given by Tanatar and Ceperley for use in density functional calculations. As model systems serve a circular few-electron quantum dot and a square lattice of dots. For single dots, electronic structure calculations are performed using both energy functionals for the self-consistent solution of the Kohn-Sham equations. The results are compared with those of a numerical diagonalization of the many-body Hamiltonian.