Thermomechanical properties of a single hexagonal boron nitride sheet

Abstract

Using atomistic simulations we investigate the thermodynamical properties of a single atomic layer of hexagonal boron nitride (h-BN). The thermal induced ripples, heat capacity, and thermal lattice expansion of large scale h-BN sheets are determined and compared to those found for graphene (GE) for temperatures up to 1000 K. By analyzing the mean square height fluctuations $< h^2>$ and the height-height correlation function $H(q)$ we found that the h-BN sheet is a less stiff material as compared to graphene. The bending rigidity of h-BN: i) is about 16% smaller than the one of GE at room temperature (300 K), and ii) increases with temperature as in GE. The difference in stiffness between h-BN and GE results in unequal responses to external uniaxial and shear stress and different buckling transitions. In contrast to a GE sheet, the buckling transition of a h-BN sheet depends strongly on the direction of the applied compression. The molar heat capacity, thermal expansion coefficient and the Gruneisen parameter are estimated to be 25.2 J\,mol$^{-1}$\,K$^{-1}$, 7.2$\times10^{-6}$K$^{-1}$ and 0.89, respectively

Suppression of intrinsic roughness in encapsulated graphene

“…Our roughness measurement of suspended graphene is lower than previously reported [20] and in excellent agreement with molecular dynamics simulations [41][42][43]. Tensile strain fields in graphene can suppress the anharmonic coupling between bending and stretching modes and lead to reduced roughness [44].…”

Thermal transport across graphene and single layer hexagonal boron nitride

“…[1][2][3] Hexagonal boron nitride (h-BN), which has two-dimensional (2D) sp 2 honeycomb structures similar to that of graphene, has recently attracted much attention because of its excellent mechanical strength and thermal properties. [4][5][6][7] Emergence of 2D materials with atomic-layer structures, such as graphene, h-BN, MoS 2 , and WSe 2 , which have excellent physical properties, provides an opportunity of substituting silicon-based micro/nano-electronics. An important issue before large-scale applications of these materials is their heat dissipation performance, especially when they are supported on a substrate, as in most scenarios.…”

Lattice thermal conductivity of borophene from first principle calculation

“…On the other hands, the boron-boron bonds in borophene are nearly as strong as the carbon-carbon bonds in graphene21. That is to say, the borophene possess outstanding mechanical property as well22. With these remarkable properties, borophene will hold promise for possible applications ranging from electronic to photovoltaic devices.…”