Chuck-Hou Yee edited tuning2.tex  over 7 years ago

Commit id: 596d0ea225d4c935f8b115bd75ed66cea05449ae

deletions | additions      

       

Using the convex hull, we can assess the stability of the reactants and products reported in experiment. In Fig.~\ref{fig:ehulls}, Fig.~\ref{fig:lcso-ehull},  we plot the energies relative to the convex hull for all reported compounds. Negative values are stability energies against decomposition. We find that La2CuS2O2 and La2CuSO3 are highly unstable at nearly 500meV/atom above the hull. Additionally, LaCuSO is marginally unstable at 23meV/atom above the hull, but this is indistinguishable from zero given the error bars of the current method. In hindsight, we could have predicted that the proposed compounds would not have formed and instead have decomposed into: \begin{align*}  \text{La}_2\text{CuS}_2\text{O}_2 &\rightarrow \text{La}_2\text{SO}_2 + \text{CuS} \\  4 \text{La}_2\text{CuS}\text{O}_3 &\rightarrow 3 \text{La}_2\text{SO}_2 + 4\text{Cu} + \text{La}_2\text{SO}_6