arXiv subjects

Héctor Abruña

Publications and source records attributed to Héctor Abruña.

3 recordsLinked to original sources

arXiv2026

A geometric basis for materials families in inorganic solids

The thermodynamic stability of inorganic solids spans a vast compositional space, yet materials scientists have long organized their intuition around a manageable number of materials families. Here we show that this organization has a precise geometric basis. The formation-energy convex hull of all inorganic compounds from the Materials Project, spanning 92-dimensional elemental composition space, is captured to near DFT accuracy by a polyhedron with only seven facets. Each facet corresponds to a family of materials sharing similar chemical potentials. This low-dimensional structure is not merely an economical description of energies: without retraining or structural input, the same framework reproduces trends in DFT-calculated defect energies and elemental spatial correlations in high-entropy nanoparticles. These results reveal that a small number of material families, corresponding to geometric features of composition-energy space, govern bulk stability, defect energetics, and elemental mixing, and provide a unified, interpretable framework for rapid screening across diverse materials systems.

cond-mat.mtrl-sci↗

arXiv2025

Effective Atom Theory: Gradient-Driven ab initio Materials Design

We introduce Effective Atom Theory (EAT), a framework that transforms combinatorial materials design into a smooth, gradient-driven optimization within density functional theory (DFT). Atoms are represented as probabilistic mixtures of elements, enabling gradient-based optimizers to converge to a physically realizable material in about 50 energy evaluations -- far fewer than combinatorial optimization methods. Applied to Co-Cr-Ni-V oxides for the alkaline oxygen evolution reaction (OER), EAT leads to a final recommended composition of Co0.19Cr0.06V0.31Ni0.44O.

cond-mat.mtrl-sci↗

arXiv2023

Ternary oxides of $\textit{s}$- and $\textit{p}$-block metals for photocatalytic solar-to-hydrogen conversion

Oxides containing metals or metalloids from the {\it p}-block of the periodic table ({\it e.g.}, In, Sn, Sb, Pb, Bi) are of technological interest as transparent conductors and light absorbers for solar energy conversion due to the tunability of their electronic conductivity and optical absorption. Comparatively, these oxides have found limited applications in hydrogen photoelectrolysis primarily due to their high electronegativity, which impedes electron transfer for reducing protons into hydrogen. We have shown recently that inserting {\it s}-block cations into {\it p}-block metal oxides is effective at lowering electronegativities while affording further control of band gaps. Here, we explain the origins of this dual tunability by demonstrating the mediator role of {\it s}-block cations in modulating orbital hybridization while not contributing to frontier electronic states. From this result, we carry out a comprehensive computational study of 109 ternary oxides of {\it s}- and {\it p}-block metal elements as candidate photocatalysts for solar hydrogen generation. We downselect the most desirable materials using band gaps and band edges obtained from Hubbard-corrected density-functional theory with Hubbard parameters computed entirely from first principles, evaluate the stability of these oxides in aqueous conditions, and characterize experimentally four of the remaining materials, synthesized with high phase uniformity, to validate and further develop the computational models. We thus propose nine oxide semiconductors, including CsIn$_3$O$_5$, Sr$_2$In$_2$O$_5$, and KSbO$_2$ which, to the extent of our literature review, have not been previously considered as water-splitting photocatalysts.

cond-mat.mtrl-sci↗