Constant perturbation in the tight-binding bands of a single-walled carbon nanotube

<div>Using a tight-binding calculation, we explain the origin of a large thermopower <em>S</em> in ropes of single-walled carbon nanotubes. We have shown that, by breaking the symmetric energy bands and increasing the overlap energy γ0, a larger <em>S</em> can be obtained. We have also found that a 10% increase in γ0 resulted to a thermopower that is four times as large.</div>