A quantum Monte Carlo study of a spherical jellium with an embedded impurity

We study the effects of a model impurity in a spherical jellium with quantum Monte Carlo (QMC) methods. The closed-shell energies and densities of jellium spheres have been studied previously using density functional theory (DFT) as well as QMC methods~[1,2]. In this study, we begin by reproducing the previous results. Second, we add an impurity to model the transition between de-localized jellium states and localized atomic-like states in correlated metallic systems. We obtain the phase space diagram of the system using Hartree--Fock, several DFT approximations and QMC methods. The differences between methods are further analyzed by comparing the ground state densities. Finally, using the inverse susceptibility scheme, we obtain the effective exchange-correlation potential and compare it with exciting approximations of DFT. \\[4pt] [1] L. M. Almeida et. al., Phys. Rev. B {\bf 66}, 075115 (2002).\\[0pt] [2] F. Sottile et. al., Phys. Rev. B {\bf 64}, 045105 (2001) and P. Ballone et. al,. Phys. Rev. B {\bf 45}, 6293 (1992).