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Suekuni, Koichiro*; Lee, C. H.*; Tanaka, Hiromi*; Nishibori, Eiji*; Nakamura, Atsushi*; Kasai, Hidetaka*; Mori, Hitoshi*; Usui, Hidetomo*; Ochi, Masayuki*; Hasegawa, Takumi*; et al.
Advanced Materials, 30(13), p.1706230_1 - 1706230_6, 2018/03
Times Cited Count：51 Percentile：89.35(Chemistry, Multidisciplinary)Thermoelectric materials for highly efficient devices must satisfy conflicting requirements of high electrical conductivity and low thermal conductivity. In this paper, we studied the crystal structure and phonon dynamics of tetrahedrites (Cu,Zn)
(Sb,As)
S
. The results revealed that the Cu atoms in a planar coordination are rattling, which effectively scatter phonons. These findings provide a new strategy for the development of highly efficient thermoelectric materials with planar coordination.
Iimura, Soshi*; Matsuishi, Satoru*; Miyakawa, Masashi*; Taniguchi, Takashi*; Suzuki, Katsuhiro*; Usui, Hidetomo*; Kuroki, Kazuhiko*; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; et al.
Physical Review B, 88(6), p.060501_1 - 060501_5, 2013/08
Times Cited Count：26 Percentile：71.33(Materials Science, Multidisciplinary)
(As
,P
) using realistic three-dimensional 10-orbital tight-binding modelNagai, Yuki; Nakamura, Hiroki; Suzuki, Katsuhiro*; Usui, Hidetomo*; Kuroki, Kazuhiko*; Machida, Masahiko
Journal of the Physical Society of Japan, 80(Suppl.B), p.SB021_1 - SB021_4, 2011/12
Times Cited Count：0 Percentile：0(Physics, Multidisciplinary)We calculate spin susceptibility on the basis of the multi-orbital random-phase approximation with use of the realistic three-dimensional 10-orbital tight-binding model for an iron-based superconductor BaFe(As,P) which seems to have gap-nodes. We show that the shape of nodes on the Fermi surface for BaFe(As,P) is distinguishable according to inelastic neutron scattering experiments. Our results are consistent with the recent neutron scattering experiments for BaFe(As,P) with Tc = 30 K.
-like spin resonance in the iron-based nodal superconductor BaFe
(As
P
) observed using inelastic neutron scatteringIshikado, Motoyuki; Nagai, Yuki; Kodama, Katsuaki; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Wakimoto, Shuichi; Nakamura, Hiroki; Machida, Masahiko; Suzuki, Katsuhiro*; et al.
Physical Review B, 84(14), p.144517_1 - 144517_5, 2011/10
Times Cited Count：26 Percentile：70.69(Materials Science, Multidisciplinary)We performed inelastic neutron scattering on a powder sample of iron-based superconductor BaFe(AsP) with 
= 30 K. Although this system is expected to have line nodes in its superconducting order parameter, we have observed spin resonance at the same scattering vector as that appeared in the -wave iron-based superconductors without line nodes. Moreover, the resonance enhancement, which can be a measure of the area of sign reversal between the hole and electron Fermi surfaces (FSs), is comparable to those without line nodes. These facts indicate that the sign reversal between the FSs is still dominant in this system, and the line nodes should create only limited area of sign-reversal on a single FS. Hence the system can hold higher Tc than the other iron-based superconductors with nodal symmetry, such as LaFePO
and KFeAs (
10 K).
Ishikado, Motoyuki; Nagai, Yuki; Kodama, Katsuaki; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Mizuno, Fumio; Wakimoto, Shuichi; Nakamura, Hiroki; Machida, Masahiko; et al.
no journal, ,
Three years have passed since the discovery of iron-based superconductors, its maximum superconducting transition temperature () is 55 K, resulting in second highest material system next to cuprate high- superconductors. Among various material systems in iron-based superconductors, we have systematically studied on LaFeAsOF
(
=28 K) of first discovered system and BaFe(As,P) which have recently attracted tremendous attention by the discovery of line nodes in its order parameter. In the session, we present recent results on "spin fluctuation and superconductivity on LaFePO
", and "symmetry of order parameter on BaFe(As,P) by inelastic neutron scattering" studied by the chopper spectrometer 4SEASONS (J-PARC).
(As,P)Ishikado, Motoyuki; Nagai, Yuki; Kodama, Katsuaki; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Wakimoto, Shuichi; Nakamura, Hiroki; Machida, Masahiko; Suzuki, Katsuhiro*; et al.
no journal, ,
In this study, we have performed inelastic neutron scattering measurement on 36g powder sample of optimally-doped BaFe(As,P) whose superconducting order parameter is expected to have line node by Fermi chopper spectrometer 4SEASONS in J-PARC. Unexpectedly, we have observed spin resonance at same 
-position and nearly identical resonance enhancement ration to other iron-based superconducctors with fully-gapped 
-wave. We will discuss about the possible superconducting gap symmetry based on our experimental results.
superconductorsIshikado, Motoyuki; Kodama, Katsuaki; Wakimoto, Shuichi; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Mizuno, Fumio; Nagai, Yuki; Nakamura, Hiroki; Machida, Masahiko; et al.
no journal, ,
Among various iron-based superconductors, we have systematically studied on LaFeAsOF (=28 K) and BaFe(As,P) (=31 K) by the Fermi chopper spectrometer 4SEASONS (J-PARC). We will discuss the possible relation between high- superconductivity and magnetic fluctuation based on our inelastic neutron scattering results.
(As,P) with nodal gap symmetryIshikado, Motoyuki; Kodama, Katsuaki; Wakimoto, Shuichi; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Nagai, Yuki; Nakamura, Hiroki; Machida, Masahiko; Suzuki, Katsuhiro*; et al.
no journal, ,
In this study, we performed inelastic neutron scattering measurement on 36g polycrystalline powder sample of optimally-doped BaFe(AsP) using a Fermi chopper spectrometer 4SEASONS in J-PARC. We observed strong spin resonance at the same -position similar to those of other iron-based superconductors with fully-gapped -wave. We will discuss about the possible superconducting gap symmetry and what causes relatively high-
of this material based on our inelastic neutron scattering results.
(As,P)Ishikado, Motoyuki; Nagai, Yuki; Kodama, Katsuaki; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Mizuno, Fumio; Wakimoto, Shuichi; Nakamura, Hiroki; Machida, Masahiko; et al.
no journal, ,
We report systematic studies on Fe-based superconductors LaFeAsOF (
=28 K) and BaFe(As,P) ( =31 K) by using inelastic neutron scattering measurement.
(As,P) with =30KIshikado, Motoyuki; Nagai, Yuki; Kodama, Katsuaki; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Wakimoto, Shuichi; Nakamura, Hiroki; Machida, Masahiko; Suzuki, Katsuhiro*; et al.
no journal, ,
In this study, we performed inelastic neutron scattering measurement on 36g polycrystalline powder sample of optimally-doped BaFe(As,P) using Fermi chopper spectrometer 4SEASONS in J-PARC. Unexpectedly, we observed spin resonance at the same -position and nearly identical resonance enhancement ratio to other iron-based superconductors with fully-gapped -wave. We will discuss about the possible superconducting gap symmetry based on our inelastic neutron scattering experiment and theoretical calculations.
Ishikado, Motoyuki; Kodama, Katsuaki; Wakimoto, Shuichi; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Mizuno, Fumio; Nagai, Yuki; Nakamura, Hiroki; Machida, Masahiko; et al.
no journal, ,
We have systematically studied nodal iron-based superconductor LaFePO (=5 K) and BaFe(As,P) (=30 K) by using Fermi chopper spectrometer 4SEASONS (J-PARC) and Triple Axis Spectrometer (TAS-1) at JRR-3. In the session, we will discuss the relation between superconductivity and spin fluctuation.
