Many-body effects on the electronic and optical properties of strained semiconducting carbon nanotubes

We present many-body ab initio calculations of the electronic and optical properties of semiconducting zigzag carbon nanotubes under uniaxial strain. The GW approach is utilized to obtain the quasiparticle band gaps and is combined with the Bethe-Salpeter equation to obtain the optical absorption spectrum. We find that the dependence of the electronic band gaps on strain is more complex than previously predicted based on tight-binding models or density functional theory. In addition, we show that the exciton energy and exciton binding energy depend significantly on strain, with variations of tens of milli-electron-volts per percent strain, but despite these strong changes the absorbance is found to be nearly independent of strain. Our results provide new guidance for the understanding and design of optomechanical systems based on carbon nanotubes.