Investigating Phase Transitions in Multifunctional Materials under Extreme Conditions

Abstract

Multifunctional materials combine electrical, magnetic, optical, thermal and mechanical responses within a single compound, and these responses are often controlled by structural and electronic phase transitions. When such materials are exposed to extreme conditions such as ultra-high pressure, cryogenic or very high temperature, intense electromagnetic fields and rapid shock loading, their phase behavior can change dramatically, giving rise to new polymorphs, metastable states and emergent functionalities that do not exist under ambient conditions. This article reviews the physical principles that govern these transformations, the experimental platforms used to create and probe extreme states, and the characterization methods that reveal changes in crystal structure, bonding and electronic order. Particular attention is given to pressure-induced structural transitions, thermally driven and shock-driven transformations, ferroelectric and multiferroic responses, and pressure-stabilized superconductivity. The role of first-principles calculations and data-driven models in predicting transition pathways is also discussed. Finally, the main experimental and theoretical challenges are outlined together with promising directions for the design of next-generation functional materials.