8 citations · 12 across the 7 of their papers we have counts for
7 papers
Spin-orbital exchange as a route to intertwined dipole-quadrupole orbital order in MnVO under strong trigonal crystal field
Hiroki Nakai, Yusuke Nomura
Orbitally degenerate systems provide a promising platform for realizing novel quantum phases driven by spin-orbital exchange interactions, as described by the Kugel-Khomskii model.…
Quantum-geometry-driven exact ferromagnetic ground state in a nearly flat band
Taisei Kitamura, Hiroki Nakai, Hosho Katsura +1
We construct a Hubbard model with a nearly flat band whose quantum geometry can be tuned independently of the energy dispersion and the Coulomb interaction. We show that, when the…
Quantum geometric ferromagnetism by singular saddle point
Taisei Kitamura, Hiroki Nakai, Akito Daido +1
We propose ferromagnetism that occurs in electrons at a saddle point with band touching, which we call the singular saddle point. At the singular saddle point, the divergent quantu…
Spinor ice correlation in flat-band electronic states on kagome and pyrochlore lattices with spin-orbit coupling
Hiroki Nakai, Masafumi Udagawa, Chisa Hotta
We investigate the emergence and transformation of pinch-point singularities in the excitation spectrum of electronic flat band systems on kagome and pyrochlore lattices with spin-…
Spin amplitude wave due to dipole-quadrupole hybridization in spin-1 pyrochlore magnets
Hiroki Nakai, Chisa Hotta
We explore the quantum pseudospin-1 pyrochlore magnet featuring Fe-based spinel oxides that addresses the formation of amplitude-modulated spin-density waves. We propose tha…
Pinch-point spectral singularity from the interference of topological loop states
Masafumi Udagawa, Hiroki Nakai, Chisa Hotta
Pinch point is a spectral discontinuity found in the neutron diffraction image of spin ice. Similar spectral singularity is commonly observed in a broad range of systems that have…
Deriving quantum spin model for a zigzag-chain ytterbium magnet with anisotropic exchange interactions
Hidehiro Saito, Hiroki Nakai, Chisa Hotta
We derive a quantum spin Hamiltonian of the spin-1/2 zigzag chain realized in a rare earth ytterbium-based magnetic insulator, YbCuS2. This material undergoes a transition at 0.95K…