  We propose a device for studying the Fermi-Hubbard model with long-range
Coulomb interactions using an array of quantum dots defined in a semiconductor
two-dimensional electron gas system. Bands with energies above the lowest
energy band are used to form the Hubbard model, which allows for an
experimentally simpler realization of the device. We find that depending on
average electron density, the system is well described by a one- or two-band
Hubbard model. Our device design enables the control of the ratio of the
Coulomb interaction to the kinetic energy of the electrons independently to the
filling of the quantum dots, such that a large portion of the Hubbard phase
diagram may be probed. Estimates of the Hubbard parameters suggest that a
metal-Mott insulator quantum phase transition and a d-wave superconducting
phase should be observable using current fabrication technologies.
