Oxides with High Entropy

New material discovery hinges on creative routes through thermodynamic and kinetic landscapes. High-entropy oxides (HEOs) offer one such pathway, where multiple cations randomly occupy a sublattice, creating a high degree of configurational disorder. This talk explores how kinetic trapping of these configurations—through both bulk and thin-film synthesis—enables the formation of metastable, chemically disordered yet structurally ordered phases. I will present a "bulk ceramic factory" approach to probe phase stability across equimolar and non-equimolar rock salt systems, establishing predictive rules for synthesizability. Using pulsed laser deposition, we unlock novel kinetic relaxation pathways to tune lattice properties, nanostructure evolution, and functionality in epitaxial films. One example of such functional high-entropy oxides is transparent, low-resistivity Srx(Ti,Cr,Nb,Mo,W)O3 perovskites. Altogether, our work demonstrates a unified framework for entropy-enabled design of complex oxides, expanding the discovery space for materials with transformative electronic, optical, and magnetic properties.