84 citations · 990 across the 49 of their papers we have counts for
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Topological Semimetal KAlGe with Novel Electronic Instability
Toshiya Ikenobe, Takahiro Yamada, Jun-ichi Yamaura +6
Compounds with the anti-PbFCl structure exhibit a variety of electronic instabilities and intriguing physical properties. NaAlSi and NaAlGe are similar topological nodal-line semim…
Odd-parity multipole order in the spin-orbit coupled metallic pyrochlore PbReO
Yuki Nakayama, Daigorou Hirai, Hajime Sagayama +6
The pyrochlore oxide Pb2Re2O7-δ (PRO) is a candidate spin-orbit-coupled metal (SOCM) that exhibits a structural phase transition with inversion symmetry breaking. In this study, we…
Successive phase transitions of the spin-orbit-coupled metal Cd2Re2O7 probed by high-resolution synchrotron x-ray diffraction
Daigorou Hirai, Atsuhito Fukui, Hajime Sagayama +2
The 5d pyrochlore oxide superconductor Cd2Re2O7 (CRO) has attracted significant interest as a spin-orbit-coupled metal (SOCM) that spontaneously undergoes a phase transition to an…
Fermi surface and light quasi particles in hourglass nodal chain metal \b{eta}-ReO2
Daigorou Hirai, Takahito Anbai, Takako Konoike +8
Quantum oscillations in magnetic torque and electrical resistivity were measured to investigate the electronic structure of \b{eta}-ReO2, a candidate hourglass nodal chain metal (D…
Linear Trimer Formation by Three-Center-Four-Electron Bonding in RuP
Daigorou Hirai, Keita Kojima, Naoyuki Katayama +3
In molecules like hydrogen, most chemical bonds are formed by sharing two electrons from each atom in the bonding molecular orbital (two-center-two-electron (2c2e) bonding). There…
Electronic Properties of Pyrochlore-Type Ca2Ir2O7
Yuki Nakayama, Yoshihiko Okamoto, Daigorou Hirai +1
The electrical resistivity, magnetic susceptibility, and heat capacity of sintered samples of Ca2Ir2O7, in which pentavalent Ir atoms with 5d4 electron configuration form a pyrochl…
Dimensional reduction and incommensurate dynamic correlations in the triangular-lattice antiferromagnet CaReOCl
S. A. Zvyagin, A. N. Ponomaryov, J. Wosnitza +7
The observation of spinon excitations in the triangular antiferromagnet CaReOCl reveals a quasi-one-dimensional (1D) nature of magnetic correlations, in…
Pyrochlore Oxide Hg2Os2O7 on Verge of Metal-Insulator Boundary
Kota Kataoka, Daigorou Hirai, Akihiro Koda +3
Semimetallic osmium pyrochlore oxide Cd2Os2O7 undergoes a magnetic transition to an all-in-all-out (AIAO)-type order at 227 K, followed by a crossover to an AIAO insulator at aroun…
Interplay between quadrupolar and magnetic interactions in 5 double perovskite BaMgReO under pressure
Hiroto Arima, Yoshiaki Oshita, Daigorou Hirai +2
We measured the electrical resistivity, AC magnetic susceptibility, and specific heat of the cubic double perovskite BaMgReO under pressure. The application of pressure lea…
Phase transition in the 5d1 double perovskite Ba2CaReO6 induced by high magnetic field
Hajime Ishikawa, Daigorou Hirai, Akihiko Ikeda +6
Magnetic properties of an antiferromagnetic double perovskite oxide Ba2CaReO6, where Re6+ (5d1) ions with large spin-orbit coupling are arranged on the face-centered-cubic lattice,…
Extremely large magnetoresistance in the hourglass Dirac loop chain metal β-ReO
Daigorou Hirai, Takahito Anbai, Shinya Uji +2
The transport and thermodynamic properties of -ReO crystallizing in a nonsymmorphic structure were studied using high-quality single crystals. An extremely large magnetore…
Anisotropic Triangular Lattice Realized in Rhenium Oxychlorides A3ReO5Cl2 (A = Ba and Sr)
Daigorou Hirai, Takeshi Yajima, Kazuhiro Nawa +2
We report the synthesis, crystal structure, and magnetic properties of two new quantum antiferromagnets A3ReO5Cl2 (A = Sr and Ba). The crystal structure is isostructural with the m…
Possible quadrupole order in tetragonal Ba2CdReO6 and chemical trend in the ground states of 5d1 double perovskites
Daigorou Hirai, Zenji Hiroi
The synthesis and physical properties of the double perovskite (DP) compound Ba2CdReO6 with the 5d1 electronic configuration are reported. Three successive phases originating from…
Kitaev Spin Liquid Candidate OsxCl3 Comprised of Honeycomb Nano-Domains
K. Kataoka, D. Hirai, T. Yajima +11
An osmium chloride with the chemical formula of OsxCl3 (x = 0.81) was synthesized and its crystal structure and thermodynamic properties were investigated. OsxCl3 crystallizes in a…
Antiferromagnetic long-range order in double-perovskite SrMgReO
Shang Gao, Daigorou Hirai, Hajime Sagayama +3
The double-perovskite ABB'O with heavy transition metal ions on the ordered B' sites is an important family of compounds to study the interplay between electron correlation…
Detection of multipolar orders in the spin-orbit-entangled 5d Mott insulator Ba2MgReO6
Daigorou Hirai, Hajime Sagayama, Shang Gao +4
In electronic solids with strong spin-orbit interactions (SOIs), the spin and orbital degrees of freedom of an electron are quantum mechanically entangled, which may result in an e…
Spin-orbit-coupled metal candidate PbRe2O6
Satoshi Tajima, Daigorou Hirai, Takeshi Yajima +3
We study the lead rhenium oxide PbRe2O6 as a candidate spin-orbit-coupled metal (SOCM), which has attracted much attention as a testing ground for studying unconventional Fermi liq…
Successive Symmetry Breaking in a Jeff = 3/2 Quartet in the Spin-Orbit Coupled Insulator Ba2MgReO6
Daigorou Hirai, Zenji Hiroi
We report on the cubic double perovskite Ba2MgReO6 containing Re6+ ions with the 5d1 electron configuration. Resistivity, magnetization, and heat capacity measurements using single…
"Visible" 5d orbital states in a pleochroic oxychloride
Daigorou Hirai, Takeshi Yajima, Daisuke Nishio-Hamane +7
Transition metal compounds sometimes exhibit beautiful colors. We report here on a new oxychloride Ca3ReO5Cl2 which shows unusually distinct pleochroism; that is, the material exhi…
One-dimensionalization by Geometrical Frustration in the Anisotropic Triangular Lattice of the 5d Quantum Antiferromagnet Ca3ReO5Cl2
Daigorou Hirai, Kazuhiro Nawa, Mitsuaki Kawamura +2
We report on the emergence of antiferromagnetic spin chains from two-dimensionally aligned spins on the anisotropic triangular lattice (ATL) in the insulating calcium rhenium oxych…
Split Fermi Surfaces of the Spin-Orbit-Coupled Metal Cd2Re2O7 Probed by de Haas-van Alphen Effect
Yasuhito Matsubayashi, Kaori Sugii, Hishiro T. Hirose +5
The superconducting pyrochlore oxide Cd2Re2O7 shows a structural transition with inversion symmetry breaking (ISB) at Ts1 = 200 K. A recent theory [L. Fu, Phys. Rev. Lett. 115, 026…
Fabrication of (111)-oriented Ca0.5Sr0.5IrO3/SrTiO3 superlattices; a designed playground for honeycomb physics
Daigorou Hirai, Jobu Matsuno, Hidenori Takagi
We report the fabrication of (111)-oriented superlattice structures with alternating 2m-layers (m = 1, 2, and 3) of Ca0.5Sr0.5IrO3 perovskite and two layers of SrTiO3 perovskite on…
Spin and Orbital Contributions to Magnetically Ordered Moments in 5d Layered Perovskite Sr2IrO4
S. Fujiyama, H. Ohsumi, K. Ohashi +5
The ratio of orbital (L) and spin (S) contributions to the magnetically ordered moments of a 5d transition metal oxide, Sr2IrO4 was evaluated by non-resonant magnetic x-ray diffrac…
Pseudogap behavior of RuP probed by photoemission spectroscopy
K. Sato, D. Ootsuki, Y. Wakisaka +8
We have studied the electronic structure of RuP and related Ru pnictides using photoemission spectroscopy. Ru 3d core-level and valence-band spectra of RuP show that the Ru valence…