Frontier in the diamond anvil cell techniques for ultrahigh pressure generation

The diamond anvil cell (DAC) has become a principal tool for high-pressure research in muti-fields such as physics, earth, and planetary sciences, because of its ability to the realization of megabar pressures and thousands of degrees. Nevertheless, the strain on the culet of single crystal diamond at high loads leads to the conventional DAC having a 400 GPa limit. To date, based on the conventional DAC, several new designs were innovatively proposed, such as the double stage DAC (ds-DAC) and toroidal DAC. They are both capable to reach pressures above 600 GPa, and even static pressures of more than 1.0 TPa are achieved using ds-DAC. All these progresses promote the exploration of unique properties and new matters in a remarkable extended pressure range. Here, the typical characteristics and experimental methods of these interesting and important ultrahigh-pressure technologies are reviewed, the strengths and limitations are summarized, and an outlook on the development of ultrahigh-pressure technology is also provided. These exciting results will further stimulate breakthrough discoveries for ultrahigh-pressure studies.