Elasticity of hexagonal boron nitride: Inelastic x-ray scattering measurements

Abstract

The five independent elastic moduli of single-crystalline hexagonal boron nitride ($h$-BN) are determined using inelastic x-ray scattering. At room temperature the elastic moduli are in units of GPa ${\mathrm{C}}_{11}=811$, ${\mathrm{C}}_{12}=169$, ${\mathrm{C}}_{13}=0$, ${\mathrm{C}}_{33}=27.0$, and ${\mathrm{C}}_{44}=7.7$. Our experimental results are compared with predictions of ab initio calculations and previously reported incomplete datasets. These results provide solid background for further theoretical advances and quantitative input to model elasticity in boron nitride (BN) nanotubes.