Carboxylated Carbon Nanotubes under External Electrical Field: An Ab Initio Investigation

Carboxylated semiconductor and metallic carbon nanotubes under transverse electrical fields are investigated through density functional theory based on first-principles calculations. The external field polarizes the system, resulting in an induced electric dipole moment toward the incident field with the modulus directly dependent on the field strength. The structural and electronic properties of the resulting system due to the orbital hybridization between the nanotube and COOH states are shown to be affected by the applied field. These results open new perspectives for different potential uses, such as to enhance the capacity of the composite to bind and characterize other substances, especially polar molecules, and as mechanisms to monitor the bound substances or control electron injection or detection, by varying the external field through a controlled application.