Structures, stability, mechanical and electronic properties of a-boron and its twined brother a*-boron

TL;DR

This study uses first-principles calculations to analyze the structures, stability, and properties of a-boron and a*-boron, revealing their potential as superhard semiconducting phases with distinct configurations and stability profiles.

Contribution

It introduces the structural and electronic characteristics of a-boron and a*-boron, highlighting their stability and potential as superhard semiconductors, which were not previously characterized.

Findings

a*-boron is less stable than a-boron but more stable than beta- and gamma-boron

Both phases are dynamically and mechanically stable

They exhibit potential as superhard semiconducting materials

Abstract

The structures, stability, mechanical and electronic properties of a-boron and its twined brother a*-boron have been studied by first-principles calculations. Both a-boron and a*-boron consist of equivalent icosahedra B12 clusters in different connecting configurations of "3S-6D-3S" and "2S-6D-4S", respectively. The total energy calculations show that a*-boron is less stable than a-boron but more favorable than beta-boron and Gamma-boron at zero pressure. Both a-boron and a*-boron are confirmed dynamically and mechanically stable. The mechanical and electronic properties of a-boron and a*-boron indicate that they are potential superhard semiconducting phases of element boron.