Abstract
We performed density functional theory (DFT) calculations to investigate the adsorption of atomic hydrogen (H) on the wrapping axis of nonpolar arm-chair (5,5) and chiral (8,4) boron nitride nanotubes (BNNTs) with a view toward understanding the chemisorption-induced polarization field in BNNTs. The adsorption of H along the zigzag B-N bonds that lie on the wrapping axis of the BNNT enhances the macroscopic polarization field. Depending on whether the B or N site near the edge of the nanotube is adsorbed with H, the direction of the polarization field, as well as the work function of the tube ends, can be changed significantly. The relationship between the chemical effect as well as the geometric distortion of the tube caused by chemisorption and the induced polarization were investigated, respectively. The results have implications for the application of BNNTs as electron emitters.