To study the interiors of planets, it is necessary to reproduce the high-pressure environments of deep planetary regions in the laboratory. Advances in high-pressure generation technology mean that deeper regions of larger planets can be studied. A group led by Associate Professor Sakai at GRC has successfully generated 5 million atmospheres of pressure, significantly exceeding the pressure at Earth’s core (3.64 million atmospheres). Conventional Diamond anvil cell (DAC) typically had a pressure generation limit of around 3 million atmospheres as a high-pressure apparatus. While previous studies occasionally reported incidentally high pressures, subsequent experiments failed to reproduce these results, indicating a lack of reproducibility in the experimental technique. In this study, by shaping the diamond tip into a hemispherical form to clamp the sample, pressures exceeding 4 million atmospheres were achieved in all five experiments conducted, demonstrating high reproducibility. One of these experiments even reached 5 million atmospheres. This pressure corresponds to the pressure throughout the mantle of a super-Earth with several times the mass of Earth. Furthermore, this pressure corresponds to the predicted metallization pressure for hydrogen, a promising candidate for room-temperature superconductors. Applications are anticipated not only in Earth and planetary deep science but also in the field of condensed matter physics. These research results were published in High Pressure Research, an international journal in the field of high-pressure science. The issue commemorates the 29th International Conference on Advanced Research in Pressure Technology (AIRAPT-29), held in Matsuyama in October 2025.
Takeshi Sakai, Satoru Nakamura, Shuto Fukuda, Sotaro Iwatsu, Yuki Nakamoto, Katsuya Shimizu, Hirokazu Kadobayashi & Saori Kawaguchi-Imada, 5 Mbar generation by using diamond anvil cell with semi-ball-like tip, High Pressure Research, doi:10.1080/08957959.2026.2627367