Aluminum nanorods subject to bending and twisting distortions: Optical response modulations using quantum mechanical simulations

Understanding how the optical response of a metal nanostructure modulates with respect to the various geometrical distortions are crucial for developing novel optical devices. In the present work, using first principles time-dependent density-functional-theory calculations, we explore the optical response modification of aluminum nanorods subjected to bending and twisting distortions. We vary the bending angle in the range of 5°-90° and twisting angle in the range of 1°-6°. We analyzed the optical excitations using the transition density plots. We found that bending and twisting distortions cause dramatic modifications in the optical absorption spectrum via gradual disappearance of longitudinal and transverse plasmon modes. In addition, the distortions resulted in significantly less absorption of the light in comparison to the undistorted aluminum nanorod.