Scientific Challenge

The energy transition is, at its heart, a materials problem. Catalysts that split water without platinum, magnetocalorics that refrigerate without hydrofluorocarbons, and electrodes that store charge reversibly all depend on placing a material at a narrow operating point in a high-dimensional compositional space. The scientific question is physical: which features of the electronic structure actually decide whether a material sits at that operating point, and which are incidental? The functional target is macroscopic, but the control variable — Fermi-level position relative to a pseudogap, d-band filling, site-resolved d-band centre — is electronic and atomic. Compositional design becomes predictive only when those control variables are isolated cleanly enough to be tuned on purpose.

Our Approach

We take problems where a clean electronic-structure control parameter exists, so that a trend across composition or site substitution can be read as a causal mechanism rather than a statistical pattern. Studies are designed factorially — hole-doping against electron-doping at the same site, isovalent metal pairs across groups, anion substitution at fixed valence electron count — so that the variable doing the work is isolated by construction.

Disorder is treated as the object of study rather than a numerical inconvenience, and methods are chosen to match the physics: Green’s-function coherent potential approximation for substitutional alloys, explicit supercells where short-range order matters, high-throughput screening along controlled compositional axes, and Lichtenstein-formalism exchange extraction where the question is about exchange topology. No single method is a house method; the question decides the tool.

We also take seriously the step from a local descriptor to a collective response. A favourable d-band centre is not a catalyst, and a large local moment is not a magnet. When we report a Curie temperature, we also report the exchange competition parameter that says how much of it survives the cancellation between ferromagnetic and antiferromagnetic pathways.

Key Insights & Achievements

• Fermi-level engineering of itinerant magnetism. In B2-ordered FeRh under substitutional disorder, hole- and electron-doping on the magnetic sublattice resolve the chemical-versus-magneto-volume question: Fermi-level position relative to the minority-spin pseudogap, not the lattice parameter, decides whether the Curie temperature collapses or holds — establishing d-band filling as a predictive control variable for itinerant ferromagnets.
• Site-resolved descriptors for catalysis. In bimetallic Janus MXenes, factorial screening across metal pairs and anions shows that site-resolved d-band asymmetry — not a sublattice-averaged descriptor — controls hydrogen adsorption near thermoneutrality, and identifies the regime (magnetic exchange splitting on one sublattice) where the local descriptor breaks down.
• Doping pathways to noble-metal-free catalysis. In layered transition-metal carbides and nitrides, targeted electronic-structure engineering through early-transition-metal doping brings hydrogen adsorption into the thermoneutral window without requiring platinum-group metals.
• Exchange topology as a design handle. Across all-d-metal and Zn-based Heusler magnetocalorics, mapping the competition between ferromagnetic and antiferromagnetic exchange pathways identifies compositional routes to room-temperature operation and unconventional critical behaviour.

Collectively, these results establish that macroscopic function in energy-relevant itinerant systems can be traced to a small number of electronic-structure control parameters, and that identifying those parameters cleanly is what makes compositional design predictive rather than exploratory.

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