Elasticity, Flexibility, and Ideal Strength of Borophenes
Abstract
The mechanical properties of 2D boron—borophene—are studied by first‐principles calculations. The recently synthesized borophene with a 1/6 concentration of hollow hexagons (HH) is shown to have in‐plane modulus C up to 210 N m−1 and bending stiffness as low as D = 0.39 eV. Thus, its Foppl–von Karman number per unit area, defined as C/D, reaches 568 nm−2, over twofold higher than graphene's value, establishing the borophene as one of the most flexible materials. Yet, the borophene has a specific modulus of 346 m2 s−2 and ideal strength of 16 N m−1, rivaling those (453 m2 s−2 and 34 N m−1) of graphene. In particular, its structural fluxionality enabled by delocalized multicenter chemical bonding favors structural phase transitions under tension, which result in exceptionally small breaking strains yet highly ductile breaking behavior. These mechanical properties can be further tailored by varying the HH concentration, and the boron sheet without HHs can even be stiffer than graphene against tension. The record high flexibility combined with excellent elasticity in boron sheets can be utilized for designing advanced composites and flexible devices.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 11, 2017
- Source ID
- 10.1002/adfm.201605059
Entities
People
- Boris I Yakobson
- Evgeni S Penev
- Yang Yang
- Zhuhua Zhang
Organizations
- Air Force Office of Scientific Research
- Nanjing University of Aeronautics and Astronautics
- National Science Foundation
- Rice University