Novel superconducting structures of BH 2 under high pressure

• Published in: Physical chemistry chemical physics : PCCP Vol. 21; no. 10; pp. 5466 - 5473
• Main Authors: Yang, Wen-Hua, Lu, Wen-Cai, Li, Shan-Dong, Xue, Xu-Yan, Zang, Qing-Jun, Ho, K M, Wang, C Z
• Format: Journal Article
• Language: English
• Published: England 06.03.2019
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/C9CP00310J

The crystal structures of boron hydrides in a pressure range of 50-400 GPa were studied using the genetic algorithm (GA) method combined with first-principles density functional theory calculations. BH4 and BH5 are predicted to be thermodynamically unstable. Two new BH2 structures with Cmcm and C2/c space group symmetries, respectively, were predicted, in which the B atoms tend to form two-dimensional sheets. The calculated band structures showed that in the pressure range of 50-150 GPa, the Cmcm-BH2 phase has very small gaps, while the C2/c-BH2 phase at 200-400 GPa is metallic. The superconductivity of the C2/c-BH2 structure was also investigated, and electron-phonon coupling calculations revealed that the estimated Tc values of C2/c-BH2 are about 28.18-37.31 K at 250 GPa.