22 citations · 50 across the 18 of their papers we have counts for
19 papers
Chiral Antiferromagnetism from Momentum-Space Resonance in a 2D Semiconductor
R. Okuma, T. Ikenobe, Y. Fujisawa +28
Understanding the principles governing the emergence of chiral quantum phases is a fundamental challenge, not only for uncovering new mechanisms of quantum-state formation but also…
Field-tuned incommensurate fan phase in an Ising-like triangular antiferromagnet
D. Flavián, R. Okuma, P. Manuel +3
Using single-crystal neutron diffraction we report the observation of a field-tuned incommensurate phase in a field range just below magnetization saturation in the Ising-like tria…
Raman spectroscopy of van der Waals topological magnet GdGaI
Nan Jiang, Yijin Zhang, Yujie Xia +9
We report polarization-resolved Raman spectroscopy of a van der Waals compound GdGaI that is a candidate for excitonic insulators. By combining the symmetry analysis with density f…
Stabilizing Itinerant Electrons in a Corner-Sharing Kagomé Oxide Nd4Os3ZnO14
Ryutaro Okuma, Yuita Fujisawa, Chia-Hsiu Hsu +8
Kagome oxides provide a fertile platform for exploring exotic electronic states arising from geometrical frustration and characteristic band topology. Here, we report the synthesis…
Quasi-One-Dimensional Electronic Nature of Ta4SiTe4 Underlying the Giant Thermoelectric Performance
Hironari Isshiki, Ayumu Tabata, Masafumi Horio +13
Ta4SiTe4 is a one-dimensional van der Waals material that exhibits an exceptionally large thermoelectric power factor below room temperature. However, since this material has been…
Molecular-Orbital Degeneracy Lifting and Suppression of a Flat-Band Metal in a Tetrahedral Cluster System NbSeI
Keita Kojima, Youichi Yamakawa, Ryutaro Okuma +7
The lifting of degenerate electronic states has been extensively studied in transition metal compounds, where diverse quantum phenomena arise from the degrees of freedom of d elect…
Muon Knight shift as a precise probe of the superconducting symmetry of SrRuO
Hisakazu Matsuki, Rustem Khasanov, Jonas A. Krieger +8
Muon spin rotation (SR) measurements of internal magnetic field shifts, known as the muon Knight shift, is used for determining pairing symmetries in superconductors. While this…
Superconductivity in Ternary Zirconium Telluride Zr6RuTe2
Kosuke Yuchi, Haruka Matsumoto, Daisuke Nishio-Hamane +5
Zr6CoAl2-type Zr6RuTe2 is found to show bulk superconductivity below the superconducting transition temperature Tc = 1.1 K, according to the electrical resistivity, magnetization,…
Cubic ReSTe as a High-Performance Thermoelectric Material
Haruka Matsumoto, Hiroto Isomura, Keita Kojima +5
We report thermoelectric properties of sintered samples of undoped, W-doped, and Sb-doped ReSTe crystallized in a cubic MoSBr-type structure. All samples exhibited p-type thermoele…
From continuum excitations to sharp magnons via transverse magnetic field in the spin-1/2 Ising-like triangular lattice antiferromagnet Na2BaCo(PO4)2
Leonie Woodland, Ryutaro Okuma, J. Ross Stewart +2
We report high-resolution inelastic neutron scattering measurements of the excitation spectrum in large single crystals of the spin-1/2 triangular lattice Ising-like antiferromagne…
Uncovering hidden Fermi surface instabilities through visualizing unconventional quasiparticle interference in CeTe3
B. R. M. Smith, Y. Fujisawa, P. Wu +14
The charge density wave (CDW) state is a widespread phenomenon in low-dimensional metals/semimetals. The spectral weight of the associated folded bands (shadow bands) can be an int…
Superconductivity in Hexagonal Zr6CoAl2-Type Zr6RuBi2 and Zr6FeBi2
Kosuke Yuchi, Daisuke Nishio-Hamane, Keita Kojima +3
We report the synthesis and electronic properties of polycrystalline samples of Zr6MBi2 (M = Ru and Fe) crystallizing in the hexagonal Zr6CoAl2-type structure. Based on their elect…
Selective synthesis and crystal chemistry of candidate rare earth Kitaev materials: honeycomb and hyperhoneycomb NaPrO
Ryutaro Okuma, Kylie MacFarquharson, Radu Coldea
Rare earth oxides have attracted interest as a platform for studying frustrated magnetism arising from bond dependent anisotropic interactions. Ordered rock salt compounds NaPr…
Compass-model physics on the hyperhoneycomb lattice in the extreme spin-orbit regime
Ryutaro Okuma, Kylie MacFarquharson, Roger D. Johnson +3
The physics of spin-orbit entangled magnetic moments of and transition metal ions on a honeycomb lattice has been much explored in search for unconventional magnetic orde…
Emergent topological magnetism in Hund's excitonic insulator
R. Okuma, K. Yamagami, Y. Fujisawa +14
Analogous to the charged electron-electron pair condensation in superconductors, an excitonic insulator (EI) represents Fermi surface instability due to spontaneous formation and c…
Superconductivity in Ternary Zirconium Telluride Zr6MTe2 with 3d Transition Metals
Haruka Matsumoto, Youichi Yamakawa, Ryutaro Okuma +2
We report the synthesis, electronic properties, and electronic states of Zr6MTe2 (M = Cr, Mn, Fe, and Co), which is isostructural to a recently discovered superconductor family Sc6…
Negative-chirality order in kagome antiferromagnet CdCu(OH)(NO)HO
Yoshihiko Ihara, Ryoga Hiyoshi, Masakazu Shimohasi +4
The neutron diffraction and nuclear magnetic resonance (NMR) measurements have been used to microscopically analyze the magnetic structure in the kagome antiferromagnet C…
Magnetic frustration in a van der Waals metal CeSiI
Ryutaro Okuma, Clemens Ritter, Gøran J. Nilsen +1
The realization of magnetic frustration in a metallic van der Waals (vdW) coupled material has been sought as a promising platform to explore novel phenomena both in bulk matter an…
Phase diagram of multiferroic KCuAsO(OD)
Gøran J. Nilsen, Virginie Simonet, Claire V. Colin +6
The layered compound KCuAsO(OD), comprising distorted kagome planes of Cu ions, is a recent addition to the family of type-II multiferroics. Previous…