Temperature and carrier density dependence of electron effective mass and bandgap in semiconductor carbon nanotubes at elevated temperature: Analytical calculations.

The effects of temperature and carrier density on the self-energy of electrons in semiconductor carbon nanotubes (CNTs) are theoretically studied by using the Matsubara Green's function approach. We show that the bandgap is slightly changed whereas the electron effective mass is strongly affected by the temperature and electron density. Furthermore, an interesting discrepancy between the results obtained from the screening dynamical approximation and that from the Hartree-Fock approximation is shown. Specifically, the calculated quantities are compared to the results obtained in a recent experiment, and a good agreement for the energy shift is seen. These results could help to clarify the role of the Coulomb interaction and the correlation and exchange energy on the optical properties of CNTs in a wide range of temperature and density. [ABSTRACT FROM AUTHOR]