Charge and spin addition energies of a one-dimensional quantum dot

We derive the effective action for a one-dimensional electron island formed between a double barrier in a single-channel quantum wire including the electron spin. Current and energy addition terms corresponding to charge and spin are identified. The influence of the range and the strength of the electron interaction and other system parameters on the charge and spin addition energies and on the excitation spectra of the modes confined within the island is studied. We find by comparison with experiment that spin excitations in addition to nonzero range of the interaction and inhomogeneity effects are important for understanding the electron transport through one-dimensional quantum islands in cleaved-edge-overgrowth systems.