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What can Mott insulators teach us about density-functional theory (and vice versa)?

N. A. Lima·L. N. Oliveira·K. Capelle
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Abstract

We study the Mott insulating phase of the one-dimensional Hubbard model using a local-density approximation (LDA) that is based on the Bethe Ansatz (BA). Unlike conventional functionals, the BA-LDA has an explicit derivative discontinuity. We demonstrate that as a consequence of this discontinuity the BA-LDA yields the correct Mott gap, independently of the strength of the correlations. A convenient analytical formula for the Mott gap in the thermodynamic limit is also derived. We find that in one-dimensional quantum systems the contribution of the discontinuity to the full gap is more important than that of the band-structure gap, and discuss some consequences this finding has for electronic-structure calculations.

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N. A. Lima, L. N. Oliveira, K. Capelle. 2002-09-13. What can Mott insulators teach us about density-functional theory (and vice versa)?. https://doi.org/10.1209/epl%2Fi2002-00261-y

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