Addition Energy Spectra of Semiconductor Quantum Dots

Advances in the semiconductor technologies allow the realization of quantum dot structure in which a finite number of electrons are confined by an artificial potentials [1–3]. The number of electrons in a quantum dot, denoted N , which can also be controlled experimentally, affects many physical properties of the quantum dot. By changing the quantum dot size and the number of electrons, far-infrared absorption [3–7], capacitance spectroscopy [8], and conductance measurements [2,3] determine the tunneling conductance and capacitance resulting from the competition of quantum confinements and Coulomb interactions. Recently, Tarucha and his coworkers probed the electronic states of a fewelectron quantum dot through single-electron tunneling spectroscopy [4]. They also measured the effects of spin configuration and confirmed Hund’s rule favoring the filling of parallel spins by applying tunable magnetic fields to the quantum dots. Furthermore, Macucci et al. have calculated the shell-filling behavior of two-dimensional cylindrical quantum dots within the framework of density functional theory [9,10]. Many-body effects due to the electron-electron interactions show a broad range of electronic structures similar to those of the real atoms. The capacitive energy of up to thirteen electrons is obtained through a self-consistent total energy calculation for model three-dimensional quantum dots. The explicit electron-spin interactions are taken into account via spin density functional theory, which properly describes the spin effects of atomic systems. The outline of this paper is as follows. In Sec. II, we concisely present our theoretical method. The calculated results and discussion are shown in Sec. III. A brief summary is given in Sec. IV.