FORCE For Science

High P-T experiments can be used to understand deep Earth and planetary materials (Earth and Planetary Sciences); discover new materials with useful electrical, optical, and mechanical properties; stimulate quantum effects (Materials Physics and Engineering); and synthesize previously unknown compounds (Chemistry). Extreme conditions, including high pressure and high temperature, are critical for creating new materials and studying their properties, and for investigating the structure and dynamics of planetary interiors.

 

The scientific impact of high pressure research has been emphasized through recent surveys and white papers. Most recently, the need for large volume, high pressure equipment not currently existing in the US was identified as a major priority in the latest NSF sponsored NAS Decadal Survey for Earth Sciences. High pressure materials research is important for the future of our nation’s prosperity because it enables the discovery and development of new technologically useful materials and processes.

 

By introducing pressure as an additional variable (complementing temperature and composition), a wide range of novel phenomena and unexpected materials properties can be discovered, with applications in Earth and planetary science as well as materials technology. When samples are treated at high P-T simultaneously, many new and potentially useful transformations occur. Broadly speaking, pressure stabilizes phases of higher density, favors higher cation coordination numbers and oxidation states, induces electron delocalization, and retards the release of volatiles, both thermodynamically and kinetically. When such materials can be “quenched” to ambient conditions, many new properties can be investigated, provided the sample is large enough (milligrams or larger rather than micrograms). In situ measurements of sample properties under high P-T conditions in the multianvil press, such as electrical conductivity and ultrasonic measurements, can also track behavior under equilibrium operando conditions and create synergies with synchrotron-based multianvil and diamond anvil cell (DAC) measurements.

 

DAC studies coupled with in situ spectroscopy and synchrotron X-ray diffraction are critical parallel techniques to identify targets for large-scale synthesis and recovery in multianvil presses. Thus, DAC and multianvil studies are complementary and synergistic. We are fortunate to have extensive expertise in both areas at ASU. Once large high density multianvil samples are available, they can be used for dynamic compression using gas gun or laser techniques that will further expand the phase space available using these shock methods.