Electronic structure via potential functional approximations

The universal functional of Hohenberg and Kohn is given as a coupling-constant integral over the density as a functional of the potential [1]. Conditions are derived under which potential-functional approximations are variational. Construction via this method and imposition of these conditions are shown to greatly improve the accuracy of the non-interacting kinetic energy needed for orbital-free Kohn-Sham calculations. This result provides a direct route to a self-consistent, orbital-free theory for the electronic structure of matter within the Kohn-Sham framework. It solely requires an approximation to the non-interacting density as a functional of the potential, which, so far, has been derived for simple systems [2,3]. \\[4pt] [1] A. Cangi, D. Lee, P. Elliott, K. Burke, E. K. U. Gross, Phys. Rev. Lett. 106, 236404, (2011).\\[0pt] [2] A. Cangi, D. Lee, P. Elliott, K. Burke, Phys. Rev. B 81, 235128, (2010).\\[0pt] [3] P. Elliott, D. Lee, A. Cangi, K. Burke, Phys. Rev. Lett. 100, 256406, (2008).