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Although dopants have been extensively employed to promote ferroelectricity in hafnia films, their role in stabilizing the responsible ferroelectric nonequilibrium Pca21 phase is not well understood. In this work, using first-principles computations, we investigate the influence of nearly 40 dopants on the phase stability in bulk hafnia to identify dopants that can favor formation of the polar Pca21 phase. Although no dopant was found to stabilize this polar phase as the ground state, suggesting that dopants alone cannot induce ferroelectricity in hafnia, Ca, Sr, Ba, La, Y, and Gd were found to significantly lower the energy of the polar phase with respect to the equilibrium monoclinic phase. These results are consistent with the empirical measurements of large remnant polarization in hafnia films doped with these elements. Additionally, clear chemical trends of dopants with larger ionic radii and lower electronegativity favoring the polar Pca21 phase in hafnia were identified. For this polar phase, an additional bond between the dopant cation and the second nearest oxygen neighbor was identified as the root-cause of these trends. Further, trivalent dopants (Y, La, and Gd) were revealed to stabilize the polar Pca21 phase at lower strains when compared to divalent dopants (Sr and Ba). On the basis of these insights, we predict that the lanthanide series metals, the lower half of alkaline earth metals (Ca, Sr, and Ba) and Y as the most suitable dopants to promote ferroelectricity in hafnia. [ABSTRACT FROM AUTHOR]

Mining of currently available and evolving materials databases to discover structure-chemistry-property relationships is critical to developing an accelerated materials design framework. The design of new and advanced polymeric dielectrics for capacitive energy storage has been hampered by the lack of sufficient data encompassing wide enough chemical spaces. Here, data mining and analysis techniques are applied on a recently presented computational data set of around 1100 organic polymers, organometallic polymers, and related molecular crystals, in order to obtain qualitative understanding of the origins of dielectric and electronic properties. By probing the relationships between crucial chemical and structural features of materials and their dielectric constant and band gap, design rules are devised for optimizing either property. Learning from this data set provides guidance to experiments and to future computations, as well as a way of expanding the pool of promising polymer candidates for dielectric applications. [ABSTRACT FROM AUTHOR]