191 citations · 658 across the 13 of their papers we have counts for
13 papers
A New Era of Excitonic Insulators
Tatsuya Kaneko, Yukinori Ohta
The fundamental idea of the excitonic insulator (EI) driven by electron-hole correlations in narrow-gap semiconductors or semimetals was originally proposed in the 1960s, and only…
Robust atomic orbital in the cluster magnet LiMoO2
N. Katayama, H. Takeda, T. Yamaguchi +5
In this study, we present a rutile-related material, LiMoO2, that becomes a cluster magnet and exhibits a spin singlet formation on a preformed molybdenum dimer upon cooling. Unlik…
Reversed Crystal-Field Splitting and Spin-Orbital Ordering in -SrCrO
T. Ishikawa, T. Toriyama, T. Konishi +2
The origin of successive phase transitions observed in the layered perovskite -SrCrO is studied by the density-functional-theory-based electronic structure calculation a…
Novel Electronic Structures of Ru-Pnictides Ru ( = P, As, Sb)
H. Goto, T. Toriyama, T. Konishi +1
Density-functional-theory-based electronic structure calculations are made to consider the novel electronic states of Ru-pnictides RuP and RuAs where the intriguing phase transitio…
Excitonic Bose-Einstein condensation in Ta2NiSe5 above room temperature
K. Seki, Y. Wakisaka, T. Kaneko +12
We show that finite temperature variational cluster approximation (VCA) calculations on an extended Falicov-Kimball model can reproduce angle-resolved photoemission spectroscopy (A…
Te 5p orbitals bring three-dimensional electronic structure to two-dimensional Ir0.95Pt0.05Te2
D. Ootsuki, T. Toriyama, M. Kobayashi +13
We have studied the nature of the three-dimensional multi-band electronic structure in the twodimensional triangular lattice Ir1-xPtxTe2 (x=0.05) superconductor using angle-resolve…
Important Roles of Te 5p and Ir 5d Spin-orbit Interactions on the Multi-band Electronic Structure of Triangular Lattice Superconductor Ir1-xPtxTe2
D. Ootsuki, T. Toriyama, M. Kobayashi +15
We report an angle-resolved photoemission spectroscopy (ARPES) study on a triangular lattice superconductor IrPtTe in which the Ir-Ir or Te-Te bond formation, the…
Exact-diagonalization study of exciton condensation in electron bilayers
T. Kaneko, S. Ejima, H. Fehske +1
We report on small-cluster exact-diagonalization calculations which prove the formation of electron-hole pairs (excitons) as prerequisite for spontaneous interlayer phase coherence…
Orthorhombic-to-Monoclinic Phase Transition of Ta2NiSe5 Induced by the Bose-Einstein Condensation of Excitons
T. Kaneko, T. Toriyama, T. Konishi +1
Using the band structure calculation and mean-field analysis of the derived three-chain Hubbard model with phonon degrees of freedom, we discuss the origin of the orthorhombic-to-m…
A BCS-BEC crossover in the extended Falicov-Kimball model: Variational cluster approach
K. Seki, R. Eder, Y. Ohta
We study the spontaneous symmetry breaking of the excitonic insulator state induced by the Coulomb interaction in the two-dimensional extended Falicov-Kimball model. Using the…
Spin gap of the three-leg S=3/2 Heisenberg tube
S. Nishimoto, Y. Fuji, Y. Ohta
The ground-state properties of the three-leg S=3/2 Heisenberg tube are studied using the density-matrix renormalization group method. We find that the spin-excitation gap associate…
Optical conductivity in the CuO double chains of PrBa_2Cu_4O_8: Consequences of charge fluctuation
R. Amasaki, Y. Shibata, Y. Ohta
We calculate the optical conductivity of the CuO double chains of PrBaCuO by the mean-field approximation for the coupled two-chain Hubbard model around quarter filling…
Charge and Orbital Ordering in the Triangular-Lattice t_{2g}-Orbital System in One Dimension: A Possible Ground State of Bi_xV_8O_{16}
Y. Shibata, Y. Ohta
We consider the possible charge and orbital ordering in a Hollandite compound Bi_xV_8O_{16}, which is a new one-dimensional triangular-lattice t_{2g}-orbital system. Using the stro…