Superhard Semiconducting Optically Transparent High Pressure Phase of Boron

2009/05/07 by E. Yu. Zarechnaya, Leonid Dubrovinsky, Natalia Dubrovinskaia +14 · 2 citations
Materials Science · Earth and Planetary Sciences · #Boron and Carbon Nanomaterials Research #High-pressure geophysics and materials #Diamond and Carbon-based Materials Research

paper · doi:10.1103/physrevlett.102.185501

openalex publication_date 2009/05/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30

Abstract

An orthorhombic (space group Pnnm) boron phase was synthesized at pressures above 9 GPa and high temperature, and it was demonstrated to be stable at least up to 30 GPa. The structure, determined by single-crystal x-ray diffraction, consists of B12 icosahedra and B2 dumbbells. The charge density distribution obtained from experimental data and ab initio calculations suggests covalent chemical bonding in this phase. Strong covalent interatomic interactions explain the low compressibility value (bulk modulus is K300=227 GPa) and high hardness of high-pressure boron (Vickers hardness HV=58 GPa), after diamond the second hardest elemental material.

Citations

• Superconductivity in Boron
• On the hardness of a new boron phase, orthorhombic γ-B28
• Efficient iterative schemes forab initiototal-energy calculations using a plane-wave basis set
• A simple measure of electron localization in atomic and molecular systems
• Ionic high-pressure form of elemental boron
• Electron Deformation Density in Rhombohedral α-Boron

Cited by

• Phase relations in boron at pressures up to 18 GPa and temperatures up to 2200<mml:mrow/>∘C
• Boron [wikipedia]