deletions | additions       diff --git a/bacoso.tex b/bacoso.tex  index 743af83..3a47663 100644  --- a/bacoso.tex  +++ b/bacoso.tex 
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% Illustrates the need for U.  % Outcome, a material that was found slightly earlier experimentally.  \emph{Electronic structure} -- The material BaCoS$_2$ is a layered antiferromagnetic Mott insulator which transitions into a metal under pressure concommitant with the suppression of the magnetic ordering temperature. Many novel superconductors are found in the region of phase diagram where magnetism is suppressed. However, it's not always the case that if (a) we have a magnetic layered magnetic compound, and (b) we suppress ordering, then (c) we necessarily get superconductivity. There are other, ill-understood factors at play, and BaCoS$_2$ is an example.  Motivated by these ideas and the observation of a pressure-tuned metal-insulator transition, there was an experimental effort to apply chemical pressure via substitution of the large sulfur ion by the smaller oxygen ion in BaCoS$_2$ to form BaCoSO. The fully-substituted end member BaCoO$_2$ was already known.  In order to determine the electronic structure, we needed the crystal structure of the material.  \emph{Structure prediction} -- it It  has been commonly assumed that LDA/GGA is sufficient. sufficient for structure prediction [citation?].  Whereas comparisons between compounds with differing compositions certainly require the corrections detailed above, it is assumed that the systematic errors in LDA/GGA energies should cancel for differing structures of a *single* given composition. We argue this is not the case. In fact, correlations are important for comparison of energetics among structures for a single composition. We use USPEX to sample the local minima in the energy landscape of the Ba-Co-S-O system with the elements in a 1:1:1:1 ratio. We allow two formula units in a unit cell. We use VASP as our DFT engine. We use spin-polarized LDA/GGA and do not include U corrections. Around 300 k-points are used, with convergence criteria EDIFF=1e-6, NELM=40.