248 / 2023-04-20 10:49:38

Exploration of novel materials under pressure

Hydrides, Superconductors, SiC, superhard materials, high pressure and high temperature, First-principle calculations

高压物理与材料科学 > 功能材料

Pressure is one of the fundamental thermodynamic variables, which can allow precisely tuning of the inter-atomic distance and alter the bonding patterns of materials, leading to the novel structures or compositions with unusual chemical and physical properties. For decades, pressure has been widely used as a powerful tool in the discovery of materi­als inaccessible at ambient conditions. Pressure enables the creation of new materials mainly through phase transitions, stabilizing new stoichiometries, producing new chemical reactions and changing the electronic properties of materials.

The purpose of this talk is to provide an overview of the recent studies undertaken by us using high pressure as a tool. Since the crystal structures of many materials are not known under pressure, an efficient CALYPSO ¹ approach for crystal structure prediction in conjunction with first-principles calculations was employed. In-situ high pressure high temperature experiments via the guidance of our theory was also partially performed. This talk will provide an overview of the research in exploration of the conventional high-T_c hydrides superconductors and new superhard materials. The following systems might be discussed: CaYH₁₂,² LaBH_x,³ A15-type ternary hydrides⁴ and SiC⁵.

References:

1. Y. Wang, J. Lv, L. Zhu, and Y. Ma, Phys. Rev. B 82, 094116 (2010).


2. Xiaowei Liang, Guoying Gao*, Yongjun Tian et al., Phys. Rev. B 99, 100505 (R) (2019).


3. Xiaowei Liang, Guoying Gao*, Yongjun Tian et al., Phys. Rev. B 104, 134501 (2021).


4. Xudong Wei, Guoying Gao*, Yongjun Tian et al., Materials Today Physics 34, 101086 (2023).


5. Rongxin Sun, Guoying Gao*, Yongjun Tian et al., Small 18, 2201212 (2022).