We report a novel insulator-insulator transition arising from the internal charge degrees of freedom in the two-dimensional quarter-filled organic salt β-(meso-DMBEDT-TTF)2PF6. The optical conductivity spectra above Tc=70 K display a prominent feature of the dimer Mott insulator, characterized by a substantial growth of a dimer peak near 0.6 eV with decreasing temperature. The dimer peak growth...

We investigate the paramagnetic-metal-to-antiferromagnetic-metal and antiferromagnetic-metal-toantiferromagnetic-insulator transitions using a slave-boson mean-field theory. To this effect, we discuss the ground state of the half-filled Hubbard model as a function of t8/t and correlation strength U, where t and t8 are the hopping amplitudes between nearest and next-nearest neighbors, respective...

Doping induced metal-insulator transition in two-dimensional Hubbard, t − U , and extended Hubbard, t − U − W , models. Abstract We show numerically that the nature of the doping induced metal-insulator transition in the two-dimensional Hubbard model is radically altered by the inclusion of a term, W , which depends upon a square of a single-particle nearest-neighbor hopping. This result is rea...

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 (Eur. Phys. J. B 13, (2000) 257). The phase boundary of the metal-insulator transition is obtained analytically as a function of the on-site Coulomb interaction at the d-orbital, the charge-transfer energ...

The topological materials have attracted much attention for their unique electronic structure and peculiar physical properties. ZrTe5 has host a long-standing puzzle on its anomalous transport properties manifested by its unusual resistivity peak and the reversal of the charge carrier type. It is also predicted that single-layer ZrTe5 is a two-dimensional topological insulator and there is poss...

We present measurements of the infrared response of the quasi-one-dimensional organic conductor (TMTSF)2FSO3 along (E‖a) and perpendicular (E‖b ′) to the stacking axis as a function of temperature. Above the metal-insulator transition related to the anion ordering the optical conductivity spectra show a Drude-like response. Below the transition an energy gap of about 1500 cm (185 meV) opens, le...

In the present paper the temperature-induced metal-insulator transition is studied in a generalized Hubbard model with correlated hopping using recently obtained expression for energy gap. The dependence of energy gap on concentration of doubly occupancy leads to increasing energy gap width with increase of temperature. Thus narrow-band system can undergo transition from a metallic state to an ...

The capability to control the type and amount of charge carriers in a material and, in the extreme case, the transition from metal to insulator, is one of the key challenges of modern electronics. By employing angle-resolved photoemission spectroscopy we find that a reversible metal to insulator transition and a fine-tuning of the charge carriers from electrons to holes can be achieved in epita...