Fullerene nanotubes in electric fields

The electronic properties of fullerene nanotubes in strong electric fields are investigated using a density-functional cluster method. It is shown that the energy difference between the open-ended and the closed configurations decreases with increasing field. The field-induced stabilization is, however, not sufficient to make the energy of the open configuration lower than the energy of the capped structure. Nanotubes, including those with a finite band gap, are found to screen large external electric fields as do perfect conductors.