JOPSS - Search Results

Journal Articles

Effect of electron correlations on spin excitation bandwidth in Ba $_{0.75}$ K $_{0.25}$ Fe $_{2}$ As $_{2}$ as seen via time-of-flight inelastic neutron scattering

Murai, Naoki; Suzuki, Katsuhiro*; Ideta, Shinichiro*; Nakajima, Masamichi*; Tanaka, Kiyohisa*; Ikeda, Hiroaki*; Kajimoto, Ryoichi

Physical Review B, 97(24), p.241112_1 - 241112_6, 2018/06

https://doi.org/10.1103/PhysRevB.97.241112

Times Cited Count：5 Percentile：25.53(Materials Science, Multidisciplinary)

We use inelastic neutron scattering (INS) to investigate the effect of electron correlations on spin dynamics in iron-based superconductor Ba $_{0.75}$ K $_{0.25}$ Fe $_{2}$ As $_{2}$ . Our INS data show a spin-wave-like dispersive feature, with a zone boundary energy of 200 meV. A first principles analysis of dynamical spin susceptibility, incorporating the mass renormalization factor of 3, as determined by angle-resolved photoemission spectroscopy, provides a reasonable description of the observed spin excitations. This analysis shows that electron correlations in the Fe-3d bands yield enhanced effective electron masses, and consequently, induce substantial narrowing of the spin excitation bandwidth. Our results highlight the importance of electron correlations in an itinerant description of the spin excitations in iron-based superconductors.

Journal Articles

Direct numerical simulations for local superconductivity above upper critical field; Theoretical confirmation of stable precursors

Machida, Masahiko; Itakura, Mitsuhiro

Physica C, 392-396(1-4), p.331 - 335, 2003/10

no abstracts in English

Journal Articles

Existence of a metallic ferromagnetic phase in models for undoped manganites

Hotta, Takashi

Physical Review B, 67(10), p.104428_1 - 104428_8, 2003/03

https://doi.org/10.1103/PhysRevB.67.104428

Times Cited Count：21 Percentile：68.18(Materials Science, Multidisciplinary)

The existence of a novel metal-insulator transition in the ferromagnetic state of models for undoped manganites is here discussed using numerical techniques applied to the $e_{rm g}$ -orbital degenerate Hubbard model tightly coupled with Jahn-Teller distortions. The ground-state phase diagram is presented in the plane defined by the electron-phonon coupling and Coulomb interaction . In contrast to the standard one-band Hubbard model for cuprates, the metallic phase is found to exist for finite values of both and in the present $e_{rm g}$ -orbital Hubbard model even at half-filling, due to the Fermi-surface topology which is incompatible with the staggered orbital ordering concomitant to the insulating phase. Based on the present results, a possible scenario for Colossal Magneto-Resistive effect is discussed in undoped manganites.

Journal Articles

Four-component relativistic calculations on the complexes between a water molecule and trivalent lanthanoid and actinoid ions

Mochizuki, Yuji*; Tatewaki, Hiroshi*

Chemical Physics, 273(2-3), p.135 - 148, 2001/11

https://doi.org/10.1016/S0301-0104(01)00483-9

Times Cited Count：23 Percentile：58.76(Chemistry, Physical)

no abstracts in English

Journal Articles

pairing and superconductivity in the negative-U Hubbard model

Betsuyaku, Hiroshi

Physical Review B, 44(2), p.871 - 874, 1991/07

https://doi.org/10.1103/PhysRevB.44.871

Times Cited Count：4 Percentile：34.38(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

High Rydberg and Auger electrons from fast projectile ions studied by zero-degree electron spectroscopy

Kawatsura, Kiyoshi*; Sataka, Masao; Naramoto, Hiroshi; Imai, Makoto; Komaki, Kenichiro*; *; *; Kanai, Yasuyuki*; Kambara, Tadashi*; *; et al.

Nuclear Instruments and Methods in Physics Research B, 53(4), p.421 - 425, 1991/04

https://doi.org/10.1016/0168-583X(91)95419-E

Times Cited Count：16 Percentile：83(Instruments & Instrumentation)

no abstracts in English

Oral presentation

Large downward renormalization of spin excitation energies in Ba $_{0.75}$ K $_{0.25}$ Fe $_{2}$ As $_{2}$ due to electron correlation effects

Murai, Naoki; Kajimoto, Ryoichi; Suzuki, Katsuhiro*; Ideta, Shinichiro*; Nakajima, Masamichi*; Ikeda, Hiroaki*; Tanaka, Kiyohisa*

no journal, ,

Using inelastic neutron scattering (INS) and angle-resolved photoemission spectroscopy (ARPES), we investigate the spin dynamics of iron-based superconductor Ba $_{0.75}$ K $_{0.25}$ Fe $_{2}$ As $_{2}$ . The INS data show a spin-wave-like dispersive feature, with a zone boundary energy of 200 meV. A random phase approximation (RPA) treatment of the dynamical spin susceptibility, incorporating the band renormalization factor of 3 derived from the ARPES measurements on the same crystals, provides a reasonable description of the observed spin excitations. This analysis shows that the experimental spin excitation peak lies at a much lower energy than the bare value, reflecting a strong renormalization of the quasiparticle band dispersion near the Fermi level due to electron correlation effect. The present results point to a unified framework that connects the magnetic response to the underlying electronic structure of the materials.

Oral presentation

Large downward renormalization of spin excitation energies in Ba $_{1-x}$ K $_{x}$ Fe $_{2}$ As $_{2}$ due to electron correlation effects

Murai, Naoki; Kajimoto, Ryoichi; Suzuki, Katsuhiro*; Ikeda, Hiroaki*; Nakajima, Masamichi*; Ideta, Shinichiro*; Tanaka, Kiyohisa*

no journal, ,

no abstracts in English

Oral presentation

Effect of electron correlations on spin excitation bandwidth in Ba $_{0.75}$ K $_{0.25}$ Fe $_{2}$ As $_{2}$ as seen via time-of-flight inelastic neutron scattering

Murai, Naoki; Kajimoto, Ryoichi; Suzuki, Katsuhiro*; Ikeda, Hiroaki*; Nakajima, Masamichi*; Ideta, Shinichiro*; Tanaka, Kiyohisa*

no journal, ,

We use inelastic neutron scattering (INS) to investigate the effect of electron correlations on spin dynamics in iron-based superconductor Ba $_{0.75}$ K $_{0.25}$ Fe $_{2}$ As $_{2}$ . Our INS data show a spin-wave-like dispersive feature, with a zone boundary energy of 200 meV. A first principles analysis of dynamical spin susceptibility, incorporating the mass renormalization factor of 3, as determined by angle-resolved photoemission spectroscopy, provides a reasonable description of the observed spin excitations. This analysis shows that electron correlations in the Fe-3d bands yield enhanced effective electron masses, and consequently, induce substantial narrowing of the spin excitation bandwidth. Our results highlight the importance of electron correlations in an itinerant description of the spin excitations in iron-based superconductors.

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Effect of electron correlations on spin excitation bandwidth in Ba $_{0.75}$ K $_{0.25}$ Fe $_{2}$ As $_{2}$ as seen via time-of-flight inelastic neutron scattering

Direct numerical simulations for local superconductivity above upper critical field; Theoretical confirmation of stable precursors

Existence of a metallic ferromagnetic phase in models for undoped manganites

Four-component relativistic calculations on the complexes between a water molecule and trivalent lanthanoid and actinoid ions

pairing and superconductivity in the negative-U Hubbard model

High Rydberg and Auger electrons from fast projectile ions studied by zero-degree electron spectroscopy

Large downward renormalization of spin excitation energies in Ba $_{0.75}$ K $_{0.25}$ Fe $_{2}$ As $_{2}$ due to electron correlation effects

Large downward renormalization of spin excitation energies in Ba $_{1-x}$ K $_{x}$ Fe $_{2}$ As $_{2}$ due to electron correlation effects

Effect of electron correlations on spin excitation bandwidth in Ba $_{0.75}$ K $_{0.25}$ Fe $_{2}$ As $_{2}$ as seen via time-of-flight inelastic neutron scattering