Density-gradient-corrected embedded atom method

Through detailed comparisons between embedded atom method (EAM) and first-principles calculations for Al, we find that EAM tends to fail when there are large electron-density gradients present. We attribute the observed failures to the violation of the uniform density approximation (UDA) underlying EAM. To remedy the insufficiency of UDA, we propose a gradient-corrected EAM model which introduces gradient corrections to the embedding function in terms of exchange correlation and kinetic energies. Based on the perturbation theory of "quasiatoms" and density-functional theory, the embedding function captures the essential physics missing in UDA and paves the way for developing more transferable EAM potentials. With Voter-Chen EAM potential as an example, we show that the gradient corrections can significantly improve the transferability of the potential.