2-electron Wigner molecules in carbon nanotube quantum dots: Excited states

The states of two electrons in a semiconducting nanotube dot are computed by exact diagonalisation of a 2-band effective mass Hamiltonian and compared to the states obtained from a molecular model. The molecular model is found to be accurate for the ground and excited states in a wide range of nanotube dots with different physical properties and this demonstrates that the quantum states are Wigner molecule-like and the electrons are strongly correlated. The first 97 excited states are examined for a physically realistic dot in the strongly correlated regime and, for these states, the molecular model is accurate to within 4%. (C) 2009 Elsevier B.V. All rights reserved.