Correlation energy of finite two-dimensional systems: Toward nonempirical and universal modeling

The capability of density-functional theory to deal with the ground state of strongly correlated low-dimensional systems, such as semiconductor quantum dots, depends on the accuracy of functionals developed for the exchange and correlation energies. Here we extend a successful approximation for the correlation energy of the three-dimensional inhomogeneous electron gas, originally introduced by Becke [J. Chem. Phys. 88, 1053 (1988)], to the two-dimensional case. The approach is based on nonempirical modeling of the correlation-hole functions satisfying a set of exact properties. Furthermore, the electron current and spin are explicitly taken into account. As a result, good performance is obtained in comparison with numerically exact data for quantum dots with varying external magnetic field, and for the homogeneous two-dimensional electron gas, respectively.