Pressure can be regarded as another dimension of science, which can dramatically change states of matter. Under pressure, materials tend to undergo structural transformation and accordingly physical and chemical properties are subject to change due to different electronic relaxations. In this presentation, I will briefly introduce contemporary high-pressure research and computational approaches mainly using density functional theory, which was also synthesized successfully in experiments.  Based on theoretically predicted sodium silicon compounds under high pressure, we stabilized a new allotrope of silicon (Si24) at ambient conditions with a quasi-direct band gap of 1.3 eV [1]. Si24 is an excellent example of how high-pressure research can address energy frontier research. Our computationally predicted iron oxide (FeO2) under pressure was also synthesized experimentally and we suggest a completely new scenario for the states of our deep lower mantle [2].

[1] D. Y. Kim, S. Stefanoski, O. Kurakevych, T. Strobel, “Synthesis of an open-framework allotrope of silicon” Nature Materials 14 169-173 (2015)

[2] Qingyang Hu, Duck Young Kim, Wenge Yang, Liuxiang Yang, Li Zhang, and Ho-Kwang Mao, “FeO2, FeOOH, and the Earth’s Oxygen-Hydrogen Cycles”, Nature 534 241-244 (2016)