The Mott metal-insulator transition in the two-band Hubbard model in infinite dimensions is studied by using the linearized dynamical mean-field theory recently developed by Bulla and Potthoff. The phase boundary of the metal-insulator transition is obtained analytically as a function of the onsite Coulomb interaction at the d-orbital, the charge-transfer energy between the dand p-orbitals and ...

We investigate the physical properties of two coupled chains of electrons, with a nearly half-filled band, as a function of the interchain hopping t ⊥ and the doping. We show that upon doping, the system undergoes a metal-insulator transition well described by a commensurate-incommensurate transition. By using bosonization and renormalization we determine the full phase diagram of the system, a...

Divergent carrier-density fluctuations equivalent to the critical opalescence of gas-liquid transition emerge around a metal-insulator critical point at a finite temperature. In contrast to the gas-liquid transitions, however, the critical temperature can be lowered to zero, which offers a challenging quantum phase transition. We present a microscopic description of such quantum critical phenom...

We study the Mott transition, antiferromagnetism, and superconductivity in layered organic conductors using the cellular dynamical mean-field theory for the frustrated Hubbard model. A d-wave superconducting phase appears between an antiferromagnetic insulator and a metal for t'/t=0.3-0.7 or between a nonmagnetic Mott insulator (spin liquid) and a metal for t'/t>or=0.8, in agreement with experi...

Highly epitaxial thin films of Pr0.7Sr0.3MnO3 were grown on (100) SrTiO3 single crystal substrates by laser ablation. Similar to other manganite compounds, these Pr0.7Sr0.3MnO3 films exhibited remarkable magnetoresistance. Application of electric currents could induce a remarkable reduction in resistivity, demonstrating a strong electroresistance effect. The ratio of the resistance variation, E...

The metal-insulator transition is characterized as a single peak in the temperature-dependent resistivity measurements; exceptions to this have never been seen in any single crystal material system. We show that by reducing a single crystal manganite thin film to a wire with a width comparable to the mesoscopic phase-separated domains inherent in the material, a second and robust metal-insulato...

We study the influence of many-particle interactions on a metal-insulator transition. We consider the two-interacting-particle problem for onsite interacting particles on a one-dimensional quasiperiodic chain, the so-called Aubry-André model. We show numerically by the decimation method and finite-size scaling that the interaction does not modify the critical parameters such as the transition p...

We study the quantum phase transition of the 1D weakly interacting Bose gas in the presence of disorder. We characterize the phase transition as a function of disorder and interaction strengths, by inspecting the long-range behavior of the one-body density matrix as well as the drop in the superfluid fraction. We focus on the properties of the low-energy Bogoliubov excitations that drive the ph...

We use a ten dimensional dual string background to study aspects of the physics of large N four dimensional SU(N) gauge theory, where its fundamental quarks are charged under a background electric field. The theory is N = 2 supersymmetric for vanishing temperature and electric field. We work in a limit where the quarks do not back-react. At zero temperature, we observe that the electric field i...

The entire family of carefully oxygen-adjusted RBaCo2O5.5 or R2Ba2Co4O11 (R1⁄4Y, Ho–La) doubleperovskite oxides is systematically investigated for the lattice parameters, A-site cation disorder, and characteristic physical properties, i.e. the metal–insulator transition, ferromagnetic transition and socalled metamagnetic transition. With increasing size of the R constituent, the lattice paramet...