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arXiv · 2102.04719

\textit{In-situ} pseudopotentials for electronic structure theory

K. Björnson·J. M. Wills·M. Alouani·O. Grånäs·P. Thunström·Chin Shen Ong·O. Eriksson
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Abstract

We present a general method of constructing \textit{in-situ} pseodopotentials from first principles, all-electron, full-potential electronic structure calculations of a solid. The method is applied to bcc Na, at equilibrium volume. The essential steps of the method involve (i) calculating an all-electron Kohn-Sham eigenstate. (ii) Replacing the oscillating part of the wavefunction (inside the muffin-tin spheres) of this state, with a smooth function. (iii) Representing the smooth wavefunction in a Fourier series, and (iv) inverting the Kohn-Sham equation, to extract the pseudopotential that produces the state generated in steps (i)-(iii). It is shown that an \textit{in-situ} pseudopotential can reproduce an all-electron, full-potential eigenvalue up to the sixth significant digit. A comparison of the all-electron theory, \textit{in-situ} pseudopotential theory and the standard nonlocal pseudopotential theory demonstrates good agreement, e.g., in the energy dispersion of the 3$s$ band state of bcc Na.

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K. Björnson, J. M. Wills, M. Alouani, O. Grånäs, P. Thunström, Chin Shen Ong, O. Eriksson. 2021-02-09. \textit{In-situ} pseudopotentials for electronic structure theory. https://arxiv.org/abs/2102.04719

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