First-principles calculations of the Youngʹs modulus of double wall boron-nitride nanotubes

By using ab-initio density functional theory and the Perdew–Burke–Ernzerh of generalized gradient approximation, the Youngʹs modulus of double-wall boron nitride nanotubes (DWBNNT) is investigated. We estimated the value of the Youngʹs modulus of (2,2) BNNT into (7,7) BNNT ((2,2)@(7,7) DWBNNT) and (2,2) BNNT into (9,9) BNNT ((2,2)@(9,9) DWBNNT) Y = 821 GPa and Y = 764 GPa, respectively. Theoretical value of 4.45 eV was obtained for the band gap energy of DWBNNTs. The calculated Youngʹs modulus for armchair nanotubes is compared to the existing experimental and theoretical data.