Electric-field-induced deformation in boron nitride nanotubes

Axial deformation of boron nitride nanotubes (BNNTs) induced by an external electric field is studied by density functional theory. It is found that the field-induced deformation can reach 1% at a field strength of around 10 V nm^-1 due to both the converse piezoelectric effect and the electrostrictive effect. This deformation is about nine times larger than that of traditional piezoceramics and can be enhanced with increasing length or decreasing diameter of the BNNTs. The corresponding volumetric work capacity is calculated to be two orders of magnitude higher than those of traditional piezoceramics.