Thermomechanical properties of a single hexagonal boron nitride sheet

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 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 , 7.2×10−6 K−1 and 0.89, respectively.Fil: Singh, Sandeep Kumar. University of Antwerp. Department of Physics; BélgicaFil: Neek Amal, M.. University of Antwerp. Department of Physics; Bélgica. Shahid Rajaee University. Department of Physics; IránFil: Costamagna, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); Argentina. University of Antwerp. Department of Physics; Bélgica. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; ArgentinaFil: Peeters, F. M.. University of Antwerp. Department of Physics; Bélgic