Document Type
Article
Publication Date
3-26-2018
Publication Title
Physical Review B
Volume
97
Issue
10
First page number:
100102
Last page number:
100107
Abstract
Binary borides has been a subject of extensive research. However, the exact compositions and crystal structures of sodium borides remained controversial. Here, using the ab initio variable-composition evolutionary algorithm, a new stable Na2B30 with I212121 symmetry (I212121-Na2B30) is found, which is -7.38meV/atom lower in energy than the Imma-Na2B30 structure reported by experimentalists. Interestingly, the Imma-Na2B30 structure is predicted to be a topological nodal line semimetal, which may result in superior electronic transport. In contrast, I212121-Na2B30 is an ultrahard semiconductor with an unprecedented open-framework structure, whose interstitial helical boron sublattice enhances its hardness and energetic stability.
Keywords
Band gap; First-principles calculations; Hardness; Complex materials; Node-line semimetals; Single crystal materials
Disciplines
Condensed Matter Physics | Physics
Language
english
Repository Citation
He, X.,
Dong, X.,
Wu, Q.,
Zhao, Z.,
Zhu, Q.,
Oganov, A. R.,
Tian, Y.,
Yu, D.,
Zhou, X.,
Wang, H.
(2018).
Predicting the Ground-state Structure of Sodium Boride.
Physical Review B, 97(10),
100102-100107.
http://dx.doi.org/10.1103/PhysRevB.97.100102