A slave-boson representation for the degenerate Hubbard model is introduced. The location of the metalto-insulator transition that occurs at commensurate densities is shown to depend weakly on the band degeneracy M . The relative weights of the Hubbard subbands depend strongly on M , as well as the magnetic properties. It is also shown that a sizable Hund’s rule coupling is required in order to...

We predict a dynamical classical superfluid-insulator transition in a Bose-Einstein condensate trapped in an optical and a magnetic potential. In the tight-binding limit, this system realizes an array of weakly coupled condensates driven by an external harmonic field. For small displacements of the parabolic trap about the equilibrium position, the condensates coherently oscillate in the array....

Highly directional-dependent metal-insulator transition is observed in epitaxial double perovskite LaBaCo2O5.5+δ films. The film exhibit metallic along [100], but remain semiconducting along [010] under application of a magnetic field parallel to the surface of the film. The physical origin for the properties is identified as in-plane tensile strain arising from oxygen vacancies. First-principl...

The insulator-metal transition was observed experimentally in nickel monoxide (NiO) at very high pressures of ~240 GPa. The sample resistance becomes measurable at about 130 GPa and decreases substantially with the pressure increase to ~240 GPa. A sharp drop in resistance by about 3 orders of magnitude has been observed at ~240 GPa with a concomitant change of the resistance type from semicondu...

Employing ab initio electronic structure calculations, we predict that trigonal tellurium consisting of weakly interacting helical chains undergoes a trivial insulator to strong topological insulator (metal) transition under shear (hydrostatic or uniaxial) strain. The transition is demonstrated by examining the strain evolution of the band structure, the topological Z2 invariant and the concomi...

Magnetic properties (coercivity and magnetization) of ferromagnetic films are strongly affected by the proximity to materials that undergo a metal to insulator transition. Here, we show that stress associated with structural changes across the metal-insulator phase transition in VO2 and V2O3 produces a magnetoelastic anisotropy in ferromagnetic films (Co and Ni) deposited on top of the oxides. ...

We report a first-order phase transition at TM=357 K in single crystal Ca2RuO4, an isomorph to the superconductor Sr2RuO4. The discontinuous decrease in electrical resistivity signals the near d e struction of the Mott insulating phase and is triggered by a s t ructural transition from the low temperature orthorhombic to a high temperature tetragonal phase. The magnetic susceptibility, which is...

The zero-temperature transition from a paramagnetic metal to a paramagnetic insulator is investigated in the dynamical mean field theory for the Hubbard model. The self-energy of the effective impurity Anderson model (on which the Hubbard model is mapped) is calculated using Wilson’s numerical renormalization group method. Results for the quasiparticle weight, the spectral function, and the sel...

with advances in genetic science, the dynamic structure of eukaryotic genome is considered as basis of gene expression regulation. long-distance communication between regulatory elements and target promoters is critical and the mechanisms responsible for this connection are just starting to emerge. chromatin insulators are key determinants of proper gene regulation and precise organization of c...

The (SrTiO3)m/(SrVO3)n d 0 − d multilayer system is studied with first principles methods through the observed insulator-to-metal transition with increasing thickness of the SrVO3 layer. When correlation effects with reasonable magnitude are included, crystal field splittings from the structural relaxations together with spin-orbit coupling (SOC) determines the behavior of the electronic and ma...