149 citations · 554 across the 28 of their papers we have counts for
24 papers · 1 filter
Ground-State Properties of the - Model for the CuO Double-Chain Structure
Tatsuya Kaneko, Satoshi Ejima, Koudai Sugimoto +1
We investigate the ground-state properties of a correlated model for the double-chain structure in cuprates. We consider the - model, in which the nearest-neighbor spin inter…
Symmetry, topology, duality, chirality, and criticality in a spin-1/2 XXZ ladder with a four-spin interaction
Mateo Fontaine, Koudai Sugimoto, Shunsuke Furukawa
We study the ground-state phase diagram of a spin-1/2 XXZ model with a chirality-chirality interaction (CCI) on a two-leg ladder. This model offers a minimal setup to study an inte…
Pump-probe spectroscopy of the one-dimensional extended Hubbard model at half filling
Koudai Sugimoto, Satoshi Ejima
By utilizing time-dependent tensor-network algorithms in the infinite matrix-product-state representation, we theoretically investigate the pump-probe spectroscopy of the one-dimen…
Wannier-Stark ladders and Stark shifts of excitons in Mott insulators
Mina Udono, Tatsuya Kaneko, Koudai Sugimoto
External-field driven energy-level discretization, such as Landau quantization or Stark localization, is one of the most intriguing phenomena in quantum systems. We investigate the…
Excitonic effects on high-harmonic generation in Mott insulators
Mina Udono, Koudai Sugimoto, Tatsuya Kaneko +1
To study excitonic effects on high-harmonic generation (HHG) in Mott insulators, we investigate pumped nonequilibrium dynamics in the one-dimensional extended Hubbard model. By emp…
Collective mode excitations and simulated -edge resonant-inelastic x-ray scattering spectra in antiferromagnetic CaRuO
Shunsuke Yamamoto, Yukinori Ohta, Koudai Sugimoto
Using the three-orbital Hubbard model, we investigate the low-energy excitation spectra in the antiferromagnetic phase of CaRuO. We calculate the dynamical susceptibilities…
Charge-ordered state satisfying the Anderson condition in LiRh2O4 arising from local dimer order
Manabu Shiomi, Keita Kojima, Naoyuki Katayama +8
We report on the charge-ordered structure of LiRh2O4 arising below the metal-insulator transition at 170 K. Structural studies using synchrotron X-rays have revealed that the charg…
Determination of the magnetic q vectors in the heavy fermion superconductor Ce3PtIn11
Naoki Shioda, Kazuki Kumeda, Hideto Fukazawa +6
An analysis with transferred hyperfine field has been performed on the spectra of the In nuclear quadrupole resonance experiments of heavy fermion superconductor CePt…
Slow dynamics of disordered zigzag chain molecules in layered LiVS2 under electron irradiation
Naoyuki Katayama, Keita Kojima, Tomoki Yamaguchi +8
Electronic instabilities in transition metal compounds often spontaneously form orbital molecules, which consist of orbital-coupled metal ions at low temperature. Recent local stru…
Light-induced switching of magnetic order in the anisotropic triangular-lattice Hubbard model
Hayato Kobayashi, Ryo Fujiuchi, Koudai Sugimoto +1
The time-dependent exact-diagonalization method is used to study the light-induced phase transition of magnetic orders in the anisotropic triangular-lattice Hubbard model. Calculat…
Successive magnetic transitions in heavy fermion superconductor Ce3PtIn11 studied by 115In nuclear quadrupole resonance
H. Fukazawa, K. Kumeda, N. Shioda +6
Nuclear quadrupole resonance (NQR) measurements were performed on the heavy fermion superconductor Ce3PtIn11 with Tc = 0.32 K. The temperature dependence of both spin-lattice relax…
Pressure-Induced Restoration of the Reversed Crystal-Field Splitting in -SrCrO
Ryo Takahashi, Tomoki Yamaguchi, Koudai Sugimoto +3
Motivated by an experimental finding that the successive phase transitions in -SrCrO observed at ambient pressure ceases to exist under high pressures, we carry out the…
Finite-temperature properties of excitonic condensation in the extended Falicov-Kimball model: Cluster mean-field-theory approach
Masahiro Kadosawa, Satoshi Nishimoto, Koudai Sugimoto +1
We study the electron-hole pair (or excitonic) condensation in the extended Falicov-Kimball model at finite temperatures based on the cluster mean-field-theory approach, where we m…
Emergence of pure spin current in doped excitonic magnets
Shunsuke Yamamoto, Koudai Sugimoto, Yukinori Ohta
An excitonic magnet hosts a condensate of spin-triplet excitons composed of conduction-band electrons and valence-band holes, and may be described by the two-orbital Hubbard model.…
Superconductivity and charge density wave under a time-dependent periodic field in the one-dimensional attractive Hubbard model
Ryo Fujiuchi, Tatsuya Kaneko, Koudai Sugimoto +2
We investigate the competition between superconductivity (SC) and charge density wave (CDW) under a time-dependent periodic field in the attractive Hubbard model. By employing the…
Typicality-Based Variational Cluster Approach to Thermodynamic Properties of the Hubbard Model
Hisao Nishida, Ryo Fujiuchi, Koudai Sugimoto +1
We develop the variational-cluster-approximation method based on the thermal-pure-quantum-state approach and apply the method to the calculations of the thermodynamic properties of…
Spin texture and spin current in excitonic phases of the two-band Hubbard model
Hisao Nishida, Shohei Miyakoshi, Tatsuya Kaneko +2
Using the mean-field approximation, we study the -space spin textures and local spin currents emerged in the spin-triplet excitonic insulator states of the two-band Hubbard mode…
Nonequilibrium dynamics in the pump-probe spectroscopy of excitonic insulators
Tetsuhiro Tanabe, Koudai Sugimoto, Yukinori Ohta
We study the nonequilibrium dynamics in the pump-probe spectroscopy of excitonic insulators using the spinless two-orbital model with phonon degrees of freedom in the time-dependen…
Strong Coupling Nature of the Excitonic Insulator State in TaNiSe
K. Sugimoto, S. Nishimoto, T. Kaneko +1
We analyze the measured optical conductivity spectra using the density-functional-theory-based electronic structure calculation and density-matrix renormalization group calculation…
Excitonic Order and Superconductivity in the Two-Orbital Hubbard Model: Variational Cluster Approach
Ryo Fujiuchi, Koudai Sugimoto, Yukinori Ohta
Using the variational cluster approach based on the self-energy functional theory, we study the possible occurrence of excitonic order and superconductivity in the two-orbital Hubb…
Low-energy excitation spectra in the excitonic phase of cobalt oxides
Tomoki Yamaguchi, Koudai Sugimoto, Yukinori Ohta
We study the excitonic phase and low-energy excitation spectra of perovskite cobalt oxides. Constructing the five-orbital Hubbard model defined on the three-dimensional cubic latti…
Orbital diamagnetic susceptibility in excitonic condensation phase
Koudai Sugimoto, Yukinori Ohta
We study the orbital diamagnetic susceptibility in excitonic condensation phase using the meanfield approximation for a two-band model defined on a square lattice. We find that, in…
Microscopic quantum interference in excitonic condensation of TaNiSe
Koudai Sugimoto, Tatsuya Kaneko, Yukinori Ohta
The microscopic quantum interference associated with excitonic condensation in TaNiSe is studied in the BCS-type mean-field approximation. We show that in ultrasonic attenu…
Spin Dynamics and Resonant Inelastic X-ray Scattering in Chromium with Commensurate Spin-Density Wave Order
Koudai Sugimoto, Zhi Li, Eiji Kaneshita +2
We theoretically investigate spin dynamics and -edge resonant inelastic X-ray scattering (RIXS) of Chromium with commensurate spin-density wave (SDW) order, based on a multi-b…