| Abstract Scope |
Material discovery via phase stability theory requires two types of inputs (i) The structure and symmetry and (ii) the specific types of electronic interactions required (such as Strong Correlation needed for open shell bonds, yet absent from DFT formalism). Missing the latter leads to the predictions of ‘false metals’ instead true insulators for 3d Mott oxides. Recent discoveries to be discussed: (i) Compounds having cell-internal degrees of freedom, but no open-shell atoms such as (A)2+(B)4+(O3)2- (e.g CaTiO3, BaTiO3, SrTiO3, and CsPbI3), have the geometric possibility of energy-lowering by symmetry breaking, thus contributing in DFT to stability and improving the insulating gaps. But compounds having cell-internal degrees of freedom and having open-shell atoms, such as ternary oxides (A)3+(B)3+(O3)2- (e.g LaFeO3, LaMnO3, and YNiO3,) will eliminate upon DFT symmetry breaking their incorrectly predicted False Metal, giving correct real insulators. (ii) By reducing degeneracies, symmetry breaking converts Strong to normal correlation. |