title: Two-electron quantum dot molecule: composite particles and the spin phase diagram.
abstract: We study a two-electron quantum dot molecule in a magnetic field by the direct diagonalization of the Hamiltonian matrix. The ground states of the molecule with the total spin S = 0 and S = 1 provide a possible realization for a qubit of a quantum computer. Switching between the states is best achieved by changing the magnetic field. Based on an analysis of the wave function, we show that the system consists of composite particles formed by an electron and flux quanta attached to it. This picture can also be used to explain the spin phase diagram.
authors.affiliation: Laboratory of Physics, Helsinki University of Technology, P.O. Box 1100, 02015 HUT, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Harju
authors.forename: S
authors.initials: S
authors.lastname: Siljamäki
authors.forename: R M
authors.initials: RM
authors.lastname: Nieminen