Predicting the Ground-state Structure of Sodium Boride

Authors

Xin-Ling He, Nankai University
Xiao Dong, Nankai University
QuanSheng Wu, École Polytechnique Fédérale de Lausanne
Zhisheng Zhao, Yanshan University
Qiang Zhu, University of Nevada, Las VegasFollow
Artem R. Oganov, Skolkovo Institute of Science and Technology; Moscow Institute of Physics and Technology; Northwestern Polytechnical University
Yongjun Tian, Yanshan University
Dongli Yu, Yanshan University
Xiang-Feng Zhou, Nankai University
Hui-Tian Wang, Nankai University; Nanjing University

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

File Format

pdf

File Size

2240 KB

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