Superior lattice thermal conductance of single-layer borophene

• Published in: NPJ 2D materials and applications Vol. 1; no. 1; pp. 1 - 7
• Main Authors: Zhou, Hangbo, Cai, Yongqing, Zhang, Gang, Zhang, Yong-Wei
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19.06.2017; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/1034; 639/766/119; Anisotropy; Atomic properties; Bonding strength; Boron; Borophene; Chemical bonds; Chemistry and Materials Science; Crystal lattices; First principles; Graphene; Heat transfer; Materials Science; Mathematical analysis; Nanotechnology; Phonons; Surfaces and Interfaces; Thermal conductivity; Thermal management; Thin Films; Transport; Two dimensional materials
• ISSN: 2397-7132; 2397-7132
• DOI: 10.1038/s41699-017-0018-2

By way of the non-equilibrium Green’s function simulations and first-principles calculations, we report that borophene, a single layer of boron atoms that was fabricated recently, possesses an extraordinarily high lattice thermal conductance in the ballistic transport regime, which even exceeds graphene. In addition to the obvious reasons of light mass and strong bonding of boron atoms, the superior thermal conductance is mainly rooted in its strong structural anisotropy and unusual phonon transmission. For low-frequency phonons, the phonon transmission within borophene is nearly isotropic, similar to that of graphene. For high-frequency phonons, however, the transmission is one-dimensional, that is, all the phonons travel in one direction, giving rise to its ultra-high thermal conductance. The present study suggests that borophene is promising for applications in efficient heat dissipation and thermal management, and also an ideal material for revealing fundamentals of dimensionality effect on phonon transport in ballistic regime. Borophene: exceptional thermal conductance Theoretical calculations reveal that borophene has a very high thermal conductance, higher than that of graphene, which currently holds the record among 2D materials. A team led by Yong-Wei Zhang at A*STAR in Singapore demonstrated that thermal transport in borophene is highly anisotropic, that is, heat is transported more efficiently in one direction than in the perpendicular one. They attributed this behavior to the fact that phonons—the quanta of the vibrations of the crystal lattice—tend to travel along a specific direction, because the bonds between boron atoms are particularly strong in that direction. The resulting thermal conductance is higher than that of any other 2D material. An improved understanding of thermal transport is relevant for applications in heat dissipation and thermal management.