Our group is dedicated to the emerging frontier of high-pressure nonequilibrium dynamics, with a particular focus on the microsecond-to-second "gap" in time scales between static high-pressure (seconds and above) and dynamic shock wave loading (nanoseconds). By developing dynamic diamond anvil cell (dDAC) techniques and microsecond time-resolved probing methods (e.g., time-resolved X-ray diffraction, TRXRD), we systematically investigate the nonequilibrium phase transition kinetics, metastable phase synthesis, and multi-field coupling behaviors (mechanical–optical–electrical) of materials during rapid compression and decompression.

Why Study High-Pressure Nonequilibrium Dynamics. Pressure, as a fundamental thermodynamic variable independent of temperature, can profoundly modulate material properties across multiple length scales, from atomic spacing and electronic orbitals to crystal structures. Conventional high-pressure science has evolved primarily along two pathways: static high pressure (e.g., diamond anvil cells, large-volume presses), characterized by extremely low strain rates (typically < 10⁻³ s⁻¹) and focused on equilibrium-state novel structures and properties; and dynamic shock compression (e.g., gas guns, laser-driven loading), featuring extremely high loading rates (> 10⁶ s⁻¹) with nanosecond time resolution, primarily addressing transient responses under extreme strain rates. However, a vast "gap" spanning from microseconds to seconds—covering several orders of magnitude in loading rate—exists between these two regimes. This gap represents the actual time window in which a multitude of nonequilibrium processes occur in nature and engineering applications.

Why Is This “Gap” Crucial? Phase transitions, chemical reactions, and energy conversion processes in materials are intrinsically kinetic; their pathways and products are strongly governed by the competition between external driving rates and internal relaxation times. Under static compression, systems have sufficient time to overcome energy barriers and evolve along thermodynamically minimum-energy pathways. Under shock loading, systems are driven by extreme over-compression and frequently bypass equilibrium pathways into metastable states. A critical question thus arises: at intermediate time scales, how do loading rates synergize with phase transition barriers and thermal fluctuations? This directly determines whether materials exhibit entirely new phase transition pathways, metastable structures, or anomalous physical properties. Nevertheless, due to the lack of experimental capabilities enabling precise control of intermediate rates combined with in situ structural characterization, this field has long remained a "blind zone," leaving numerous fundamental scientific questions unresolved.

Group Mission and Core Scientific Questions. Our group was established specifically to bridge this gap and advance high-pressure nonequilibrium dynamics as an emerging interdisciplinary field. We focus on addressing the following core scientific questions: (1) How do phase transition pathways and products depend on the coupled interplay of loading rate, pressure, and temperature? (2) What new response laws govern the mechanical, optical, and electrical properties of materials under nonequilibrium conditions? (3) Can rate-controlled synthesis be exploited to "on-demand" fabricate specific metastable phases or optimize functional properties?

High-pressure nonequilibrium dynamics is not merely a transitional "patch" between static high pressure and shock wave compression; it is an independent research direction with distinct physical content and broad application prospects. Its central scientific proposition is: When the external driving time becomes comparable to the internal relaxation time of a material, how do its structure and properties evolve? Leveraging dDAC and microsecond time-resolved probing techniques, our group has achieved a series of original contributions in this field.