Structural and electronic properties of Na-B-H compounds at high pressure

Article

关键词: GENERALIZED GRADIENT APPROXIMATION;    CRYSTAL-STRUCTURE;    SUPERCONDUCTIVITY;    TEMPERATURE;    EXCHANGE;   

DOI  :  10.1103/PhysRevB.106.174104

来源: SCIE

【 摘 要 】

Ternary hydrides are ideal candidates for high-temperature superconductivity. However, their electronic prop-erties correlate strongly with the charge transfer between their consistent elements. In this work we propose nine Na-B-H compounds, which combines charge modulation between Na and B/H atoms with pressure, with unusual structural motifs and interesting electronic properties. In the metallic Pmma NaBH3, with both ionic and covalent frameworks, formed by H atoms bonded to Na/B atoms, a low-frequency phonon dominated superconductivity is predicted with a Tc of 86.8 K, distinct from the high-frequency H-derived superconductivity associated with covalent H-based skeletons or H cages/sheets in superhydrides. Furthermore, in nonmetallic NaBHn (n = 1, 2, and 6) and R-3m NaBH3, the B atom exhibits an sp3-hybridized feature analogous to the C atom, resulting in the formation of several alkanelike B-H motifs, such as a graphanelike layer and an ethane-shaped molecule. Our work presents an important step toward the understanding of metal borohydrides.

【 授权许可】

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