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

UNLV article access

Search your library

Share

COinS