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52
Sep 19, 2013
09/13
by
K. Miyake; H. Kohno; H. Harima
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It is shown that unconventional nature of superconducting state of PrOs_4Sb_12, a Pr-based heavy electron compound with the filled-Skutterudite structure, can be explained in a unified way by taking into account the structure of the crystalline-electric-field (CEF) level, the shape of the Fermi surface determined by the band structure calculation, and a picture of the quasiparticles in f$^{2}$-configuration with magnetically singlet CEF ground state. Possible types of pairing are narrowed down...
Source: http://arxiv.org/abs/cond-mat/0302316v1
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45
Sep 24, 2013
09/13
by
A. Carrington; J. D. Fletcher; H. Harima
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We present detailed results for the amplitude and field dependence of the de Haas-van Alphen (dHvA) signal arising from the electron-like $\pi$ sheet of Fermi surface in MgB_2. Our data and analysis show that the dip in dHvA amplitude when the field is close to the basal plane is caused by a beat between two very similar dHvA frequencies and not a spin-zero effect as previously assumed. Our results imply that the Stoner enhancement factors in MgB_2 are small on both the Sigma and Pi sheets.
Source: http://arxiv.org/abs/cond-mat/0412359v1
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79
Sep 23, 2013
09/13
by
Y. Nakajima; T. Nakagawa; T. Tamegai; H. Harima
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eye 79
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We report low-temperature specific heat studies on single-crystalline ternary-iron silicide superconductor Lu$_{2}$Fe$_{3}$Si$_{5}$ with$T_c$ = 6.1 K down to $\sim T_c/20$. We confirm a reduced normalized jump in specific heat at $T_c$, and find that the specific heat divided by temperature $C/T$ shows sudden drop at $\sim T_c/5$ and goes to zero with further decreasing temperature. These results indicate the presence of two distinct superconducting gaps in Lu$_{2}$Fe$_{3}$Si$_{5}$, similar to...
Source: http://arxiv.org/abs/0801.0111v1
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62
Sep 20, 2013
09/13
by
S. H. Curnoe; H. Harima; K. Takegahara; K. Ueda
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All symmetry allowed couplings between the 4f^2-electron ground state doublet of trivalent praseodymium in PrRu4P12 and PrFe4P12 and displacements of the phosphorus, iron or ruthenium ions are considered. Two types of displacements can change the crystal lattice from body-centred cubic to simple orthorhombic or to simple cubic. The first type lowers the point group symmetry from tetrahedral to orthorhombic, while the second type leaves it unchanged, with corresponding space group reductions Im3...
Source: http://arxiv.org/abs/cond-mat/0405127v1
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6.0
Jun 30, 2018
06/18
by
K. Götze; D. Aoki; F. Lévy-Bertrand; H. Harima; I. Sheikin
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We report high field de Haas-van Alphen (dHvA) effect measurements in CeRh$_2$Si$_2$ both below and above the first-order 26 T metamagnetic transition from an antiferromagnetic to a polarized paramagnetic state. The dHvA frequencies observed above the transition are much higher than those observed below, implying a drastic change of the Fermi-surface size. The dHvA frequencies above the transition and their angular dependence are in good agreement with band-structure calculations for...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1704.02139
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55
Sep 22, 2013
09/13
by
A. Palacio-Morales; A. Pourret; G. Knebel; T. Combier; D. Aoki; H. Harima; J. Flouquet
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We report field and temperature dependent measurements of the thermoelectric power (TEP) and the Nernst effect in the itinerant metamagnet UCoAl. The magnetic field is applied along the easy magnetization c-axis in the hexagonal crystal structure. The metamagnetic transition from the paramagnetic phase at zero field to the field induced ferromagnetic (FM) state is of first order at low temperatures and becomes a broad crossover above the critical temperature $T^{\star}_{M} \sim 11$ K. The...
Source: http://arxiv.org/abs/1302.2478v1
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47
Sep 18, 2013
09/13
by
S. Ohira-Kawamura; H. Shishido; A. Yoshida; R. Okazaki; H. Kawano-Furukawa; T. Shibauchi; H. Harima; Y. Matsuda
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Elastic neutron diffraction measurements were performed on the quasi-two dimensional heavy fermion system CeRh1-xCoxIn5, ranging from an incommensurate antiferromagnet for low x to an unconventional superconductor on the Co-rich end of the phase diagram. We found that the superconductivity competes with the incommensurate antiferromagnetic (AFM) order characterized by qI=(1/2, 1/2, delta) with delta=0.298, while it coexists with the commensurate AFM order with qc=(1/2, 1/2, 1/2). This is in...
Source: http://arxiv.org/abs/0704.2336v2
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50
Sep 22, 2013
09/13
by
H. Okamura; R. Kitamura; M. Matsunami; H. Sugawara; H. Harima; H. Sato; T. Moriwaki; Y. Ikemoto; T. Nanba
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Optical conductivity [s(w)] of Ce-filled skutterudite CeRu4Sb12 has been measured at high pressure to 8 GPa and at low temperature, to probe the pressure evolution of its electronic structures. At ambient pressure, a mid-infrared peak at 0.1 eV was formed in s(w) at low temperature, and the spectral weight below 0.1 eV was strongly suppressed, due to a hybridization of the f electron and conduction electron states. With increasing external pressure, the mid-infrared peak shifts to higher...
Source: http://arxiv.org/abs/1103.0811v3
50
50
Sep 22, 2013
09/13
by
P. A Goddard; J. Singleton; R. D. McDonald; N. Harrison; J. C. Lashley; H. Harima; M. -T. Suzuki
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eye 50
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AuZn undergoes a shape-memory transition at 67 K. The de Haas van Alphen effect persists to 100 K enabling the observation of a change in the quantum oscillation spectrum indicative of a catastrophic Fermi surface reconstruction at the transition. Coexistence of both Fermi surfaces at low temperatures is suggestive of an intrinsic phase separation in the bulk of the material. In addition, a Dingle analysis reveals a sharp change in the scattering mechanism at a threshold cyclotron radius, which...
Source: http://arxiv.org/abs/cond-mat/0501108v1
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54
Sep 19, 2013
09/13
by
A. Sekiyama; H. Fujiwara; S. Imada; H. Eisaki; S. I. Uchida; K. Takegahara; H. Harima; Y. Saitoh; S. Suga
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Bulk-sensitive high-resolution photoemission was carried out on a prototype 3d1 metallic Sr1-xCaxVO3. In a strong contrast to so far reported results, the bulk spectral functions are revealed to be insensitive to x. The conservation of the density of states at the Fermi level in spite of the electron correlation is clarified by the successful suppression and deconvolution of the surface contribution. Our study has demonstrated the importance of high-energy and high-resolution photoemission...
Source: http://arxiv.org/abs/cond-mat/0206471v2
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103
Sep 18, 2013
09/13
by
S. R. Saha; H. Sugawara; Y. Aoki; H. Sato; Y. Inada; H. Shishido; R. Settai; Y. Onuki; H. Harima
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eye 103
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We report the de Haas-van Alphen (dHvA) effect and magnetoresistance in the filled-skutterudite superconductor LaRu4P12, which is a reference material of PrRu4P12 that exhibits a metal-insulator (M-I) transition at T_MI~60 K. The observed dHvA branches for the main Fermi surface (FS) are well explained by the band-structure calculation, using the full potential linearized augmented-plane-wave method with the local-density approximation, suggesting a nesting instability with q =(1,0,0) in the...
Source: http://arxiv.org/abs/cond-mat/0504602v1
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62
Sep 19, 2013
09/13
by
M. Yogi; T. Nagai; Y. Imamura; H. Mukuda; Y. Kitaoka; D. Kikuchi; H. Sugawara; Y. Aoki; H. Sato; H. Harima
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We report on Sb nuclear-quadrupole-resonance (NQR) study in filled-skutterudite compounds (Pr_1-xLa_x)Os_4Sb_12. The Sb-NQR spectra have split into two sets, arising from different Sb_12 cages containing either Pr or La, which enables us to measure two kinds of nuclear spin-lattice relaxation time T_1^Pr and T_1^La. In the normal state, the temperature (T) dependence of 1/T^Pr_1T showed almost the same behavior as that for PrOs_4Sb_12 regardless of. In contrast, 1/T^La_1T markedly decreases...
Source: http://arxiv.org/abs/cond-mat/0610215v1
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60
Sep 18, 2013
09/13
by
A. Harada; H. Mukuda; Y. Kitaoka; A. Thamizhavel; Y. Okuda; R. Settai; Y. Onuki; K. M. Itoh; E. E. Haller; H. Harima
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We report a $^{73}$Ge nuclear-quadrupole-resonance (NQR) study on novel evolution of unconventional superconductivity in antiferromagnetic (AFM) CeNiGe$_3$. The measurements of the $^{73}$Ge-NQR spectrum and the nuclear spin-lattice relaxation rate ($1/T_1$) have revealed that the unconventional superconductivity evolves inside a commensurate AFM phase around the pressure ($P$) where N\'{e}el temperature $T_{\rm N}$ exhibits its maximum at 8.5 K. The superconducting transition temperature...
Source: http://arxiv.org/abs/0809.0770v1
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58
Sep 19, 2013
09/13
by
A. Yamasaki; S. Imada; T. Nanba; A. Sekiyama; H. Sugawara; H. Sato; C. Sekine; I. Shirotani; H. Harima; S. Suga
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eye 58
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Pr 4f electronic states in Pr-based filled skutterudites PrT4X12(T=Fe and Ru; X=P and Sb) have been studied by high-resolution bulk-sensitive Pr 3d-4f resonance photoemission. A very strong spectral intensity is observed just below the Fermi level in the heavy-fermion system PrFe4P12. The increase of its intensity at lower temperatures is observed. We speculate that this is the Kondo resonance of Pr, the origin of which is attributed to the strong hybridization between the Pr 4f and the...
Source: http://arxiv.org/abs/cond-mat/0208406v2
9
9.0
Jun 28, 2018
06/18
by
K. Götze; J. Klotz; D. Gnida; H. Harima; D. Aoki; A. Demuer; S. Elgazzar; J. Wosnitza; D. Kaczorowski; I. Sheikin
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eye 9
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We report low-temperature de Haas-van Alphen (dHvA) effect measurements in magnetic fields up to 35 T of the heavy-fermion superconductor Ce$_2$PdIn$_8$. The comparison of the experimental results with band-structure calculations implies that the 4$f$ electrons are itinerant rather than localized. The cyclotron masses estimated at high field are only moderately enhanced, 8 and 14 $m_0$, but are substantially larger than the corresponding band masses. The observed angular dependence of the dHvA...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1509.02657
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54
Sep 18, 2013
09/13
by
A. Harada; S. Kawasaki; H. Mukuda; Y. Kitaoka; Y. Haga; E. Yamamoto; Y. Onuki; K. M. Itoh; E. E. Haller; H. Harima
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eye 54
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We report that a novel type of superconducting order parameter has been realized in the ferromagnetic states in UGe$_2$ via $^{73}$Ge nuclear-quadrupole-resonance (NQR) experiments performed under pressure ($P$). Measurements of the nuclear spin-lattice relaxation rate $(1/T_1)$ have revealed an unconventional nature of superconductivity such that the up-spin band is gapped with line nodes, but the down-spin band remains gapless at the Fermi level. This result is consistent with that of a...
Source: http://arxiv.org/abs/0705.2944v1
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53
Sep 18, 2013
09/13
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H. Sugawara; S. Osaki; S. R. Saha; Y. Aoki; H. Sato; Y. Inada; H. Shishido; R. Settai; Y. Onuki; H. Harima; K. Oikawa
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eye 53
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We have investigated the de Haas-van Alphen effect in the Pr-based heavy fermion superconductor PrOs$_4$Sb$_{12}$.The topology of Fermi surface is close to the reference compound LaOs$_4$Sb$_{12}$ and well explained by the band structure calculation based on the FLAPW-LDA+U method, where the 4{\it f} electrons are localized. We have confirmed a highly enhanced cyclotron effective mass 2.4$\sim7.6m_{\rm 0}$ which is apparently large compared to the usual Pr-based compounds.
Source: http://arxiv.org/abs/cond-mat/0210601v2
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67
Sep 24, 2013
09/13
by
H. Kotegawa; A. Harada; S. Kawasaki; Y. Kawasaki; Y. Kitaoka; Y. Haga; E. Yamamoto; Y. Onuki; K. M. Itoh; E. E. Haller; H. Harima
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We report on the itinerant ferromagnetic superconductor UGe_2 through ^73Ge-NQR measurements under pressure (P). The P dependence of the NQR spectrum signals a first-order transition from the low-temperature (T) and low-P ferromagnetic phase (FM2) to high-T and high-P one (FM1) around a critical pressure of P_x ~ 1.2 GPa. The superconductivity exhibiting a maximum value of T_sc=0.7 K at P_x ~ 1.2 GPa, was found to take place in connection with the P-induced first-order transition. The nuclear...
Source: http://arxiv.org/abs/cond-mat/0412311v1
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54
Sep 22, 2013
09/13
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R. D. McDonald; J. C. Lashley; J. Singleton; P. A. Goddard; F. Drymiotis; N. Harrison; H. Harima; M. -T. Suzuki; A. Migliori; J. L. Smith
texts
eye 54
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Martensites are materials that undergo diffusionless, solid-state transitions. The martensitic transition yields properties that depend on the history of the material and may allow it to recover its previous shape after plastic deformation. This is known as the shape-memory effect (SME). We have succeeded in identifying the primary electronic mechanism responsible for the martensitic transition in the shape-memory alloy AuZn by using Fermi-surface measurements (de Haas-van Alphen oscillations)...
Source: http://arxiv.org/abs/cond-mat/0501024v1
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72
Sep 20, 2013
09/13
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S. Kawasaki; M. Yashima; Y. Kitaoka; K. Takeda; K. Shimizu; Y. Oishi; M. Takata; T. C. Kobayashi; H. Harima; S. Araki; H. Shishido; R. Settai; Y. Onuki
texts
eye 72
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We report on the pressure-induced unconventional superconductivity in the heavy-fermion antiferromagnet CeIn3 by means of nuclear-quadrupole-resonance (NQR) studies conducted under a high pressure. The temperature and pressure dependences of the NQR spectra have revealed a first-order quantum-phase transition (QPT) from an AFM to PM at a critical pressure Pc=2.46 GPa. Despite the lack of an AFM quantum critical point in the P-T phase diagram, we highlight the fact that the unconventional SC...
Source: http://arxiv.org/abs/0802.2150v1
106
106
Jul 20, 2013
07/13
by
T. Yoshida; I. Nishi; A. Fujimori; M. Yi; R. G. Moore; D. -H. Lu; Z. -X. Shen; K. Kihou; P. M. Shirage; H. Kito; C. H. Lee; A. Iyo; H. Eisaki; H. Harima
texts
eye 106
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We have performed an angle-resolved photoemission study of the iron pnictide superconductor KFe2As2 with Tc 4 K. Most of the observed Fermi surfaces show almost two-dimensional shapes, while one of the quasi-particle bands near the Fermi level has a strong dispersion along the kz direction, consistent with the result of a band-structure calculation. However, hole Fermi surfaces \alpha and \zeta are smaller than those predicted by the calculation while other Fermi surfaces are larger. These...
Source: http://arxiv.org/abs/1007.2698v2
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67
Sep 23, 2013
09/13
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A. Sekiyama; H. Fujiwara; S. Imada; S. Suga; H. Eisaki; S. I. Uchida; K. Takegahara; H. Harima; Y. Saitoh; I. A. Nekrasov; G. Keller; D. E. Kondakov; A. V. Kozhevnikov; Th. Pruschke; K. Held; D. Vollhardt; V. I. Anishimov
texts
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We report high-resolution high-energy photoemission spectra together with parameter-free LDA+DMFT (local density approximation + dynamical mean-field theory) results for Sr1-xCaxVO3, a prototype 3d1 system. In contrast to earlier investigations the bulk spectra are found to be insensitive to x. The good agreement between experiment and theory confirms the bulk-sensitivity of the high-energy photoemission spectra.
Source: http://arxiv.org/abs/cond-mat/0312429v3
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47
Sep 21, 2013
09/13
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M. Kimata; T. Terashima; N. Kurita; H. Satsukawa; A. Harada; K. Kodama; A. Sato; M. Imai; K. Kihou; C. H. Lee; H. Kito; H. Eisaki; A. Iyo; T. Saito; H. Fukazawa; Y. Kohori; H. Harima; S. Uji
texts
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We report the results of the angular-dependent magnetoresistance oscillations (AMROs), which can determine the shape of bulk Fermi surfaces in quasi-two-dimensional (Q2D) systems, in a highly hole-doped Fe-based superconductor KFe$_2$As$_2$ with $T_c \approx$ 3.7 K. From the AMROs, we determined the two Q2D FSs with rounded-square cross sections, corresponding to 12% and 17% of the first Brillouin zone. The rounded-squared shape of the FS cross section is also confirmed by the analyses of the...
Source: http://arxiv.org/abs/1011.2056v1
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57
Sep 21, 2013
09/13
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N. Harrison; S. E. Sebastian; C. H. Mielke; A. Paris; M. J. Gordon; C. A. Swenson; D. G. Rickel; M. D. Pacheco; P. F. Ruminer; J. B. Schillig; J. R. Sims; A. H. Lacerda; M. T. Suzuki; H. Harima; T. Ebihara
texts
eye 57
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We report measurements of the de Haas-van Alphen effect in CeIn3 in magnetic fields extending to ~90 T, well above the Ne'el critical field of Hc ~61 T. The unreconstructed Fermi surface a-sheet is observed in the high magnetic field polarized paramagnetic limit, but with its effective mass and Fermi surface volume strongly reduced in size compared to that observed in the low magnetic field paramagnetic regime under pressure. The spheroidal topology of this sheet provides an ideal realization...
Source: http://arxiv.org/abs/0706.2387v1
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46
Sep 20, 2013
09/13
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M. Matsunami; K. Horiba; M. Taguchi; K. Yamamoto; A. Chainani; Y. Takata; Y. Senba; H. Ohashi; M. Yabashi; K. Tamasaku; Y. Nishino; D. Miwa; T. Ishikawa; E. Ikenaga; K. Kobayashi; H. Sugawara; H. Sato; H. Harima; S. Shin
texts
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Semiconducting skutterudite CeFe$_4$P$_{12}$ is investigated by synchrotron x-ray photoemission spectroscopy (PES) and x-ray absorption spectroscopy (XAS). Ce 3$d$ core-level PES and 3$d-4f$ XAS, in combination with single impurity Anderson model (SIAM) calculations, confirm features due to $f^0$, $f^1$ and $f^2$ configurations. The Ce 4$f$ density of states (DOS) indicates absence of a Kondo resonance at Fermi level, but can still be explained by SIAM with a small gap in non-$f$ DOS. While Ce...
Source: http://arxiv.org/abs/cond-mat/0601114v1
5
5.0
Jun 30, 2018
06/18
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S. Ideta; T. Yoshida; M. Nakajima; W. Malaeb; H. Kito; H. Eisaki; A. Iyo; Y. Tomioka; T. Ito; K. Kihou; C. H. Lee; Y. Kotani; K. Ono; S. K. Mo; Z. Hussain; Z. -X. Shen; H. Harima; S. Uchida; A. Fujimori
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We have performed an angle-resolved photoemission spectroscopy (ARPES) study of BaNi$_2$P$_2$ which shows a superconducting transition at $T_c$ $\sim$ 2.5 K. We observed hole and electron Fermi surfaces (FSs) around the Brillouin zone center and corner, respectively, and the shapes of the hole FSs dramatically changed with photon energy, indicating strong three-dimensionality. The observed FSs are consistent with band-structure calculation and de Haas-van Alphen measurements. The mass...
Topics: Superconductivity, Condensed Matter
Source: http://arxiv.org/abs/1401.7897
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49
Sep 20, 2013
09/13
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T. Yoshida; S. Ideta; I. Nishi; A. Fujimori; M. Yi; R. G. Moore; S. K. Mo; D. -H. Lu; Z. -X. Shen; Z. Hussain; K. Kihou; P. M. Shirage; H. Kito; C. H. Lee; A. Iyo; H. Eisaki; H. Harima
texts
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We have performed an angle-resolved photoemission study of the hole-overdoped iron pnictide superconductor KFe2As2, which shows a low Tc of ~4 K. Most of the observed Fermi surfaces show nearly two-dimensional shapes, while a band near the Fermi level shows a strong dispersion along the kz direction and forms a small three-dimensional hole pocket centered at the Z point, as predicted by band-structure calculation. However, hole Fermi surfaces of yz and zx orbital character centered at the...
Source: http://arxiv.org/abs/1205.6911v1
