Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where K. Ono is active.

Publication


Featured researches published by K. Ono.


Physical Review Letters | 2009

Universal versus Materials-Dependent Two-Gap Behaviour of the High-Tc Cuprate Superconductors: Angle-Resolved Photoemission Study of La2-xSrxCuO4

T. Yoshida; Makoto Hashimoto; S. Ideta; Atsushi Fujimori; K. Tanaka; Norman Mannella; Z. Hussain; Z.-X. Shen; Minoru Kubota; K. Ono; Seiki Komiya; Yoichi Ando; H. Eisaki; S. Uchida

We have investigated the doping and temperature dependences of the pseudogap and superconducting gap in the single-layer cuprate La2-xSrxCuO4 by angle-resolved photoemission spectroscopy. The results clearly exhibit two distinct energy and temperature scales, namely, the gap around (pi, 0) of magnitude Delta* and the gap around the node characterized by the d-wave order parameter Delta0. In comparison with Bi2212 having higher Tcs, Delta0 is smaller, while Delta* and T* are similar. This result suggests that Delta* and T* are approximately material-independent properties of a single CuO2 plane, in contrast to the material-dependent Delta0, representing the pairing strength.


Physical Review Letters | 2011

Two-dimensional and three-dimensional Fermi surfaces of superconducting BaFe2(As(1-x)P(x))2 and their nesting properties revealed by angle-resolved photoemission spectroscopy.

T. Yoshida; I. Nishi; S. Ideta; A. Fujimori; Masato Kubota; K. Ono; S. Kasahara; T. Shibauchi; Takahito Terashima; Y. Matsuda; Hiroaki Ikeda; Ryotaro Arita

T. Yoshida, I. Nishi, S. Ideta, A. Fujimori, M. Kubota, K. Ono, S. Kasahara, T. Shibauchi, T. Terashima, Y. Matsuda, H. Ikeda and R. Arita Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan JST, Transformative Research-Project on Iron Pnictides (TRIP), Chiyoda, Tokyo 102-0075, Japan KEK, Photon Factory, Tsukuba, Ibaraki 305-0801, Japan Research Center for Low Temperature and Materials Sciences, Kyoto University, Kyoto 606-8502, Japan 5 Department of Physics, Kyoto University, Kyoto 606-8502, Japan and Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-8561 (Dated: August 13, 2010)


Physical Review Letters | 2013

Dependence of carrier doping on the impurity potential in transition-metal-substituted FeAs-based superconductors.

S. Ideta; T. Yoshida; I. Nishi; Atsushi Fujimori; Yoshinori Kotani; K. Ono; Y. Nakashima; S. Yamaichi; T. Sasagawa; Makoto Nakajima; Kunihiro Kihou; Y. Tomioka; Chul-Ho Lee; Akira Iyo; H. Eisaki; Toshimitsu Ito; S. Uchida; Ryotaro Arita

In order to examine to what extent the rigid-band-like electron doping scenario is applicable to the transition metal-substituted Fe-based superconductors, we have performed angle-resolved photoemission spectroscopy studies of Ba(Fe(1-x)Ni(x))(2)As(2) (Ni-122) and Ba(Fe(1-x)Cu(x))(2)As(2) (Cu-122), and compared the results with Ba(Fe(1-x)Co(x))(2)As(2) (Co-122). We find that Ni 3d-derived features are formed below the Fe 3d band and that Cu 3d-derived ones further below it. The electron and hole Fermi surface (FS) volumes are found to increase and decrease with substitution, respectively, qualitatively consistent with the rigid-band model. However, the total extra electron number estimated from the FS volumes (the total electron FS volume minus the total hole FS volume) is found to decrease in going from Co-, Ni-, to Cu-122 for a fixed nominal extra electron number, that is, the number of electrons that participate in the formation of FS decreases with increasing impurity potential. We find that the Néel temperature T(N) and the critical temperature T(c) maximum are determined by the FS volumes rather than the nominal extra electron concentration or the substituted atom concentration.


Nature Materials | 2017

Evidence for magnetic Weyl fermions in a correlated metal

Kenta Kuroda; Takahiro Tomita; Michi-To Suzuki; Cedric Bareille; A. A. Nugroho; Pallab Goswami; Masayuki Ochi; Muhammad Ikhlas; M. Nakayama; S. Akebi; R. Noguchi; Rieko Ishii; N. Inami; K. Ono; Hiroshi Kumigashira; A. Varykhalov; Takayuki Muro; Takashi Koretsune; Ryotaro Arita; Shik Shin; Takeshi Kondo; Satoru Nakatsuji

Weyl fermions have been observed as three-dimensional, gapless topological excitations in weakly correlated, inversion-symmetry-breaking semimetals. However, their realization in spontaneously time-reversal-symmetry-breaking phases of strongly correlated materials has so far remained hypothetical. Here, we report experimental evidence for magnetic Weyl fermions in Mn3Sn, a non-collinear antiferromagnet that exhibits a large anomalous Hall effect, even at room temperature. Detailed comparison between angle-resolved photoemission spectroscopy (ARPES) measurements and density functional theory (DFT) calculations reveals significant bandwidth renormalization and damping effects due to the strong correlation among Mn 3d electrons. Magnetotransport measurements provide strong evidence for the chiral anomaly of Weyl fermions-namely, the emergence of positive magnetoconductance only in the presence of parallel electric and magnetic fields. Since weak magnetic fields (approximately 10 mT) are adequate to control the distribution of Weyl points and the large fictitious fields (equivalent to approximately a few hundred T) produced by them in momentum space, our discovery lays the foundation for a new field of science and technology involving the magnetic Weyl excitations of strongly correlated electron systems such as Mn3Sn.


Nature Communications | 2015

Quadratic Fermi node in a 3D strongly correlated semimetal

Takeshi Kondo; M. Nakayama; R. Chen; J. J. Ishikawa; E. G. Moon; T. Yamamoto; Y. Ota; W. Malaeb; H. Kanai; Y. Nakashima; Y. Ishida; Rikiya Yoshida; H. Yamamoto; M. Matsunami; Shin-ichi Kimura; N. Inami; K. Ono; Hiroshi Kumigashira; Satoru Nakatsuji; Leon Balents; Shik Shin

Strong spin–orbit coupling fosters exotic electronic states such as topological insulators and superconductors, but the combination of strong spin–orbit and strong electron–electron interactions is just beginning to be understood. Central to this emerging area are the 5d transition metal iridium oxides. Here, in the pyrochlore iridate Pr2Ir2O7, we identify a non-trivial state with a single-point Fermi node protected by cubic and time-reversal symmetries, using a combination of angle-resolved photoemission spectroscopy and first-principles calculations. Owing to its quadratic dispersion, the unique coincidence of four degenerate states at the Fermi energy, and strong Coulomb interactions, non-Fermi liquid behaviour is predicted, for which we observe some evidence. Our discovery implies that Pr2Ir2O7 is a parent state that can be manipulated to produce other strongly correlated topological phases, such as topological Mott insulator, Weyl semimetal, and quantum spin and anomalous Hall states.


Nature Communications | 2016

Suppression of the antiferromagnetic pseudogap in the electron-doped high-temperature superconductor by protect annealing

M. Horio; T. Adachi; Y. Mori; Akira Takahashi; T. Yoshida; Hiromichi Suzuki; L. C. C. Ambolode; K. Okazaki; K. Ono; Hiroshi Kumigashira; Hiroaki Anzai; M. Arita; Hirofumi Namatame; M. Taniguchi; D. Ootsuki; Kei Sawada; Masaya Takahashi; T. Mizokawa; Yoji Koike; Atsushi Fujimori

In the hole-doped cuprates, a small number of carriers suppresses antiferromagnetism and induces superconductivity. In the electron-doped cuprates, on the other hand, superconductivity appears only in a narrow window of high-doped Ce concentration after reduction annealing, and strong antiferromagnetic correlation persists in the superconducting phase. Recently, Pr1.3−xLa0.7CexCuO4 (PLCCO) bulk single crystals annealed by a protect annealing method showed a high critical temperature of around 27 K for small Ce content down to 0.05. Here, by angle-resolved photoemission spectroscopy measurements of PLCCO crystals, we observed a sharp quasi-particle peak on the entire Fermi surface without signature of an antiferromagnetic pseudogap unlike all the previous work, indicating a dramatic reduction of antiferromagnetic correlation length and/or of magnetic moments. The superconducting state was found to extend over a wide electron concentration range. The present results fundamentally challenge the long-standing picture on the electronic structure in the electron-doped regime.


Physical Review B | 2004

Effects of next-nearest-neighbor hopping of t' on the electronic structure of cuprate superconductors

K. Tanaka; T. Yoshida; A. Fujimori; D. H. Lu; Z.-X. Shen; X. J. Zhou; H. Eisaki; Z. Hussain; S. Uchida; Y. Aiura; K. Ono; T. Sugaya; Takafumi Mizuno; Ichiro Terasaki

Photoemission spectra of underdoped and lightly-doped Bi


Physical Review B | 2014

Pseudogap formation above the superconducting dome in iron-pnictides

T. Shimojima; T. Sonobe; W. Malaeb; K. Shinada; A. Chainani; Shik Shin; T. Yoshida; S. Ideta; Atsushi Fujimori; Hiroshi Kumigashira; K. Ono; Y. Nakashima; Hiroaki Anzai; M. Arita; A. Ino; Hirofumi Namatame; M. Taniguchi; Makoto Nakajima; S. Uchida; Y. Tomioka; Toshimitsu Ito; Kunihiro Kihou; C. H. Lee; Akira Iyo; H. Eisaki; Kenya Ohgushi; S. Kasahara; Takahito Terashima; Hiroaki Ikeda; T. Shibauchi

_{2-z}


Physical Review B | 2010

Mass renormalization in the bandwidth-controlled Mott-Hubbard systems SrVO 3 and CaVO 3 studied by angle-resolved photoemission spectroscopy

T. Yoshida; M. Hashimoto; T. Takizawa; A. Fujimori; Masato Kubota; K. Ono; H. Eisaki

Pb


Physical Review B | 2006

Band structure and Fermi surface of La 0.6 Sr 0.4 MnO 3 thin films studied by in situ angle-resolved photoemission spectroscopy

Akira Chikamatsu; H. Wadati; Hiroshi Kumigashira; M. Oshima; A. Fujimori; Noriaki Hamada; Tsuyoshi Ohnishi; Mikk Lippmaa; K. Ono; M. Kawasaki; Hideomi Koinuma

_z

Collaboration


Dive into the K. Ono's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

H. Eisaki

National Institute of Advanced Industrial Science and Technology

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

D. H. Lu

SLAC National Accelerator Laboratory

View shared research outputs
Top Co-Authors

Avatar

Akira Iyo

National Institute of Advanced Industrial Science and Technology

View shared research outputs
Researchain Logo
Decentralizing Knowledge