Materials at Extreme Conditions: From Planetary Interiors to Ultrafast Structural Dynamics

by Dr Valerio Cerantola (University of Milano-Bicocca)

Monday 15 Dec 2025, 14:30 → 15:30 Europe/Berlin

PH HS 3 (Physics Department)

Understanding the behaviour of materials under extreme pressures and temperatures is fundamental to constraining the structure, evolution, and dynamics of planetary interiors, from the Earth’s mantle and core to the exotic environments of ice and gas giants, and even exoplanets. These regimes span transitions between solid, liquid, plasma, and warm dense states, where structural and electronic transformations occur on timescales ranging from geological to nanosecond scales. Capturing such processes experimentally requires combining static and dynamic compression techniques with powerful, time-resolved probes.

Static compression enables access to conditions relevant to the Earth’s mantle and core, revealing slow kinetic processes, phase transitions, and their stability regions. Dynamic compression, in contrast, reaches multi-megabar pressures and thousands of kelvin on nanosecond timescales, providing insight into fast structural dynamics, transformation pathways, and the warm dense matter regime encountered in giant planets and impact events. Recent developments, such as the shock diamond anvil cell (sDAC) at the European XFEL, bridge the gap between static and large-scale laser experiments, allowing exploration of unprecedented density-temperature regimes and complex phenomena such as superionicity, metallization, and phase transitions in planetary materials.

The seminar will highlight recent results showing how these methods are applied to materials relevant to planetary interiors. Case studies include i) the phase diagram of water at multi-megabar pressures, ii) the behaviour of carbon and carbonates under static and dynamic compression, iii) iron-bearing compounds and Fe-hydrides, key to understanding Earth’s core composition and iv) hydrogen–helium demixing, which governs energy transport and magnetic field generation in gas giants such as Jupiter and Saturn.

By combining static and dynamic compression with next-generation X-ray and neutron probes, we can now observe atomic and electronic rearrangements in real time and under relevant thermodynamic conditions. This integrated approach refines our models of planetary structure and evolution, deepens our understanding of matter at high density and temperature, and promises new insights into the origins and diversity of planets within and beyond our Solar System.