title: Direct coulomb and exchange interaction in artificial atoms
abstract: We determine contributions from the direct Coulomb and exchange interactions to the total interaction in artificial semiconductor atoms. We tune the relative strengths of the two interactions and measure them as a function of the number of confined electrons. The electrons tend to have parallel spins when they occupy nearly degenerate single-particle states. We use a magnetic field to adjust the single-particle-state degeneracy, and find that the spin configurations in an arbitrary magnetic field are well explained in terms of two-electron singlet and triplet states.
authors.affiliation: Department of Physics, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan and NTT Basic Research Laboratories, 3-1, Morinosato Wakamiya, Atsugi-shi, Kanagawa 243-0198, Japan.
authors.initials: S
authors.lastname: Tarucha
authors.initials: DG
authors.lastname: Austing
authors.initials: Y
authors.lastname: Tokura
authors.lastname: van Der Wiel WG
authors.initials: LP
authors.lastname: Kouwenhoven