99 citations · 331 across the 13 of their papers we have counts for
13 papers
Excited States beyond Mott Gap in Half-Filled-Band Hubbard Model
Hisatoshi Yokoyama, Kenji Kobayashi, Tsutomu Watanabe +1
In connection with recent experiments on excitation in which Mott insulators change to conductors, we study the properties of excited states beyond the Mott gap as quasi-stationary…
Spin and Charge Fluctuations near Metal-Insulator Transition in Dimer-Type Molecular Solid
Naomichi Sato, Tsutomu Watanabe, Makoto Naka +1
Spin and charge fluctuations at vicinity of metal-to-Mott insulator transitions are studied in an organic solid with molecular dimers. The extended Hubbard model taking account of…
Phase diagram and collective excitation in excitonic insulator: from the orbital physics viewpoint
Joji Nasu, Tsutomu Watanabe, Makoto Naka +1
Excitonic insulating system is studied from the viewpoints of the orbital physics in strongly correlated electron systems. An effective model Hamiltonian for low-energy electronic…
Band and Mott Insulators and Superconductivity in Honeycomb-Lattice Ionic-Hubbard Model
Tsutomu Watanabe, Sumio Ishihara
Motivated by superconductivity (SC) in layered nitrides, we study an ionic-Hubbard model on a honeycomb lattice, which consists of two sublattices with an energy-level offset, by u…
Quantum Dielectric Fluctuation in an Electronic Ferroelectricity studied by Variational Monte-Carlo Method
Tsutomu Watanabe, Sumio Ishihara
Electronic structure and dielectric property in an electronic ferroelectricty, where electric polarization is driven by an electronic charge order without inversion symmetry, are s…
Spin-state transition and phase separation in multi-orbital Hubbard model
Ryo Suzuki, Tsutomu Watanabe, Sumio Ishihara
We study spin-state transition and phase separation involving this transition based on the milti-orbital Hubbard model. Multiple spin states are realized by changing the energy sep…