Length and boundary effects on a nanorod

We investigate length and boundary effects on the equilibrium strain of a ⟨100⟩ copper nanorod with {100} or {110} surfaces. Unlike a nanowire, a free-edged nanorod has finite length and has two more surfaces at both tip and root. Although the area of these two edge surfaces is generally much smaller than that of side surfaces, the effect of the edge surfaces should not be ignored in the equilibrium configuration of a nanorod. In this letter, an analytical model to estimate the equilibrium strain of the nanorod is proposed, and molecular statics simulations are performed to prove the proposed model. As the length of a nanorod increases, the equilibrium strain increases and converges to that of a nanowire. As for the boundary effect, we compare the equilibrium strain of a clamped nanorod with that of a free-edged nanorod.