Energetics of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>MnO</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>polymorphs in density functional theory

We report the energetics and properties of the β, α, R, γ, λ, and δ polymorphs of MnO&lt;sub&gt;2&lt;/sub&gt; within density functional theory, comparing the performance of the recently introduced SCAN functional with that of conventional exchange-correlation functionals and experiment. We find that SCAN uniquely yields accurate formation energies and properties across all MnO&lt;sub&gt;2&lt;/sub&gt; polymorphs. We explain the superior performance of SCAN based on its satisfaction of all known constraints appropriate to a semilocal exchange-correlation functional and its accurate representation of all types of orbital overlap.