Abstract

We examine the behaviour of 2 electrons on a 2 x 2 square lattice sites. The Hubbard model was used to model the system and was diagonalized using the configuration interaction method which is a variational method. The variations of the ground state energy ground state double occupied sites D, and the ground state kinetic energy  with the interaction strength (u < 0 and u > 0) were examined. The functions  and  were found to be parabolic functions of. This suggests that superconductivity is driven by both electron and hole doping.

Key words: Hubbard model, Superconductivity, Configuration interaction and Electron correlation.