Lattice mismatch induced curved configurations of hybrid boron nitride–carbon nanotubes

• A unique curved configuration is observed in freestanding hybrid boron nitride–carbon nanotubes (BN–CNTs).
• The curved configuration of BN–CNTs is due to the lattice mismatch between the C domain and the BN domain.
• The curvature of BN–CNTs decreases with growing radius of BN–CNTs and becomes ignorable when their radius is relatively large.
• A non-monotonic relationship is detected between the curvature and the composition of BN–CNTs.

A unique curved configuration is observed in freestanding hybrid boron nitride–carbon nanotubes (BN–CNTs) based on molecular dynamics simulations, which, in previous studies, was tacitly assumed as a straight configuration. The physical fundamentals of this phenomenon are explored by using the continuum mechanics theory, where the curved configuration of BN–CNTs is found to be induced by the bending effect due to the lattice mismatch between the C domain and the BN domain. In addition, our results show that the curvature of the curved BN–CNTs is determined by their radius and composition. The curvature of BN–CNTs decreases with growing radius of BN–CNTs and becomes ignorable when their radius is relatively large. A non-monotonic relationship is detected between the curvature and the composition of BN–CNTs. Specifically, the curvature of BN–CNTs increases with growing BN concentration when the molar fraction of BN atoms is smaller than a critical value 0.52, but decreases with growing BN concentration when the molar fraction of BN atoms is larger than this critical value.