Niigata University

output

19922026

most citedSciPy 1.0--Fundamental Algorithms for Scientific Computing in Python

40.2k citations

researchers with a paper here

Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.

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91 papers · 1 filter

cond-mat.str-el2026

Ultrasonic Observation of Slowing Down of Multipole Fluctuations in Sr $_{2}$ RuO $_{4}$

Ryosuke Kurihara, Mitsuhiro Akatsu, Shunsuke Yaoita +5

We performed ultrasonic measurements on the unconventional superconductor Sr $_{2}$ RuO $_{4}$ to investigate the dynamical properties of the electronic states near its superconducting tr…

cond-mat.str-el2025★ 1 cited

Paramagnetic electron-nuclear spin entanglement in HoCo2Zn20

Takafumi Kitazawa, Yasuyuki Shimura, Takahiro Onimaru +7

We investigated electron-nuclear spin entanglement in the paramagnetic ground state of the Ho-based cubic compound HoCo2Zn20. From analyses of magnetization and specific heat data,…

cond-mat.str-el2023★ 4 cited

Translational symmetry broken magnetization plateau of the S=1 antiferromagnetic Heisenberg chain with competing anisotropies

Tôru Sakai, Kiyomi Okamoto, Kouichi Okunishi +4

We investigate the S=1 antiferromagnetic quantum spin chain with the exchange and single-ion anisotropies in a magnetic field, using the numerical exact diagonalization of finite-s…

cond-mat.str-el2023★ 23 cited

Coexistence of near-EF flat band and van Hove singularity in a two-phase superconductor

Xuezhi Chen, Le Wang, Jun Ishizuka +9

In quantum many-body systems, particularly, the ones with large near-EF density states, like flat bands or van Hove singularity (VHS), electron correlations often give rise to rich…

cond-mat.str-el2023★ 23 cited

de Haas-van Alphen Oscillations for the Field Along c-axis in UTe2

Dai Aoki, Ilya Sheikin, Alix McCollam +5

We performed de Haas-van Alphen (dHvA) experiments in the spin-triplet superconductor UTe2 for magnetic field along the c-axis above 15T. Three fundamental dHvA frequencies, named…

cond-mat.str-el2022★ 1 cited

High-Field Ultrasonic Study of CeIrIn $_{5}$

Ryosuke Kurihara, Atsushi Miyake, Ryoma Tsunoda +3

We performed ultrasonic and temperature measurements under pulsed magnetic fields on CeIrIn $_{5}$ to investigate whether or not the origin of metamagnetic transition and field-induce…

cond-mat.str-el2022★ 3 cited

Pressure dependence of the magnetic ground state in CePtSi2

S. E. Dissanayake, F. Ye, W. Tian +7

CePtSi2 was reported to exhibit an antiferromagnetic order below T*=1.8 K at ambient pressure, a valence state change at ~1.2 GPa, and superconductivity in the range between 1.4 an…

cond-mat.str-el2022★ 92 cited

First Observation of de Haas-van Alphen Effect and Fermi Surfaces in Unconventional Superconductor UTe2

Dai Aoki, Hironori Sakai, Petr Opletal +11

We report the first observation of the de Haas-van Alphen (dHvA) effect in the novel spin-triplet superconductor UTe2 using high quality single crystals with the high residual resi…

cond-mat.str-el2022★ 2 cited

Unusually strong electronic correlation and field-induced ordered phase in YbCo $_{2}$

J. Valenta, N. Tsujii, H. Yamaoka +10

We report the first study of electrical resistivity, magnetization, and specific heat on YbCo $_{2}$ . The measurements on a single-phased sample of YbCo $_{2}$ bring no evidence of magne…

cond-mat.str-el2022★ 5 cited

First-principles Study of the RKKY Interaction and the Quadrupole Order in the Pr 1-2-20 systems PrT2Al20 (T=Ti, V)

Y. Iizuka, T. Yamada, K. Hanzawa +1

Electronic states and quadrupole orders in the Pr 1-2-20 systems PrT2Al20 (T=Ti, V) are investigated on the basis of the first-principles calculations. The effective 196 orbital mo…

cond-mat.str-el2022★ 27 cited

Duality, Criticality, Anomaly, and Topology in Quantum Spin-1 Chains

Hong Yang, Linhao Li, Kouichi Okunishi +1

In quantum spin-1 chains, there is a nonlocal unitary transformation known as the Kennedy-Tasaki transformation $U_{KT}$ , which defines a duality between the Haldane phase a…

cond-mat.str-el2022★ 2 cited

Elastic Soft Mode and Electric Quadrupole Response in Excitonic Insulator Candidate (Ta $_{0.952}$ V $_{0.048}$ ) $_{2}$ NiSe $_{5}$ : Contribution of Electron-Phonon Interaction

Ryosuke Kurihara, Yusuke Hirose, Sumika Sano +4

We performed ultrasonic measurements on (Ta $_{0.952}$ V $_{0.048}$ ) $_{2}$ NiSe $_{5}$ to investigate the contribution of acoustic phonons at the zone center to structural and possible exci…

cond-mat.str-el2021

Entanglement-based tensor-network strong-disorder renormalization group

Kouichi Seki, Toshiya Hikihara, Kouichi Okunishi

We propose an entanglement-based algorithm of the tensor-network strong-disorder renormalization group (tSDRG) method for quantum spin systems with quenched randomness. In contrast…

cond-mat.str-el2020★ 18 cited

Cluster glass transition and relaxation in random spinel CoGa2O4

T. Naka, T. Nakane, S. Ishii +6

We report magnetic properties in the random spinel magnet CoGa2O4. Rietveld analysis of the x-ray diffraction profile for CoGa2O4 reveals that the Co and Ga ions are distributed ra…

cond-mat.str-el2020★ 10 cited

Tensor-network strong-disorder renormalization groups for random quantum spin systems in two dimensions

Kouichi Seki, Toshiya Hikihara, Kouichi Okunishi

Novel randomness-induced disordered ground states in two-dimensional (2D) quantum spin systems have been attracting much interest. For quantitative analysis of such random quantum…

cond-mat.str-el2020★ 4 cited

Magnetic structure of Cd-doped CeIrIn $_{5}$

K. Beauvois, N. Qureshi, R. Tsunoda +6

We report the magnetic structure of nominally 10% Cd-doped CeIrIn $_{5}$ , CeIr(In $_{0.9}$ Cd $_{0.1}$ ) $_{5}$ , determined by elastic neutron scattering. Magnetic intensity was observed onl…

cond-mat.str-el2020★ 15 cited

High-Field Ultrasonic Study of Quadrupole Ordering and Crystal Symmetry Breaking in CeRhIn5

R. Kurihara, A. Miyake, M. Tokunaga +2

We performed an ultrasonic measurement for the heavy-fermion compound CeRhIn $_{5}$ to investigate the origin of the field-induced anisotropic phase in high magnetic fields. The trans…

cond-mat.str-el2019★ 3 cited

RKKY Interaction and Quadrupole Order in PrT2Al20 (T=Ti, V) Based on Effective 196 Orbital Model Extracted from First-Principles Calculation

Y. Iizuka, T. Yamada, K. Hanzawa +1

Electronic states and quadrupole orders in the 1-2-20 systems PrT2Al20 (T=Ti, V) are investigated on the basis of the first-principles band calculation. As the de Haas-van Alphen e…

cond-mat.str-el2017★ 3 cited

Quasi-two-dimensional Fermi surfaces with localized $f$ electrons in the layered heavy-fermion compound CePt $_{2}$ In $_{7}$

K. Götze, Y. Krupko, J. A. N. Bruin +8

We report measurements of the de Haas-van Alphen effect in the layered heavy-fermion compound CePt $_{2}$ In $_{7}$ in high magnetic fields up to 35 T. Above an angle-dependent threshold…

cond-mat.str-el2017★ 6 cited

Spin-wave analysis for Kagome-triangular spin system and coupled spin tubes: low-energy excitation for the cuboc order

Masahiro Ochiai, Kouichi Seki, Kouichi Okunishi

The coupled spin tube system, which is equivalent to a stacked Kagome-triangular spin system, exhibits the cuboc order -- a non-coplanar spin order with a twelve-sublattice structu…

cond-mat.str-el2017★ 22 cited

Critical Slowing Down of Quadrupole and Hexadecapole Orderings in Iron Pnictide Superconductor

Ryosuke Kurihara, Keisuke Mitsumoto, Mitsuhiro Akatsu +4

Ultrasonic measurements have been carried out to investigate the critical dynamics of structural and superconducting transitions due to degenerate orbital bands in iron pnictide co…

cond-mat.str-el2017★ 11 cited

Excitonic Phase Diagram of the Three-Chain Hubbard Model for Semiconducting and Semimetallic Ta $_{2}$ NiSe $_{5}$

Kaoru Domon, Takemi Yamada, Yoshiaki Ōno

Transition metal chalcogenide Ta $_{2}$ NiSe $_{5}$ , a promising material for the excitonic insulator, is investigated on the basis of the quasi-one-dimensional three-chain Hubbard model…

cond-mat.str-el2017★ 7 cited

Determination of the magnetic structure of CePt $_{2}$ In $_{7}$ by means of neutron diffraction

M. Raba, E. Ressouche, N. Qureshi +7

The magnetic structure of the heavy fermion antiferromagnet CePt $_{2}$ In $_{7}$ is determined using neutron diffraction. We find a magnetic wave vector $q_{M} = (1/2, 1/2, 1/2)$ , w…

cond-mat.str-el2016★ 23 cited

Three-dimensional critical phase diagram of the Ising antiferromagnet CeRh $_{2}$ Si $_{2}$ under intense magnetic field and pressure

W. Knafo, R. Settai, D. Braithwaite +3

Using novel instrumentation to combine extreme conditions of intense pulsed magnetic field up to 60~T and high pressure up to 4~GPa, we have established the three-dimensional (3D)…

Ultrasonic Observation of Slowing Down of Multipole Fluctuations in Sr2​RuO4​