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Tokunaga, Yo; Sakai, Hironori; Kambe, Shinsaku; Opletal, P.; Tokiwa, Yoshifumi; Haga, Yoshinori; Kitagawa, Shunsaku*; Ishida, Kenji*; Aoki, Dai*; Knebel, G.*; et al.
Physical Review Letters, 131(22), p.226503_1 - 226503_7, 2023/12
Times Cited Count：0 Percentile：0.00(Physics, Multidisciplinary)
Raymond, S.*; Knafo, W.*; Knebel, G.*; Kaneko, Koji; Brison, J.-P.*; Flouquet, J.*; Aoki, Dai*; Lapertot, G.*
Journal of the Physical Society of Japan, 90(11), p.113706_1 - 113706_5, 2021/11
Times Cited Count：13 Percentile：79.65(Physics, Multidisciplinary)Knafo, W.*; Knebel, G.*; Steffens, P.*; Kaneko, Koji; Rosuel, A.*; Brison, J.-P.*; Flouquet, J.*; Aoki, Dai*; Lapertot, G.*; Raymond, S.*
Physical Review B, 104(10), p.L100409_1 - L100409_6, 2021/09
Times Cited Count：38 Percentile：94.52(Materials Science, Multidisciplinary)
dependence of nuclear spin-echo decay at low temperatures in YbRhSiKambe, Shinsaku; Sakai, Hironori; Tokunaga, Yo; Hattori, Taisuke; Lapertot, G.*; Matsuda, Tatsuma*; Knebel, G.*; Flouquet, J.*; Walstedt, R. E.*
Physical Review B, 95(19), p.195121_1 - 195121_8, 2017/05
Times Cited Count：3 Percentile：16.80(Materials Science, Multidisciplinary)The authors report 
Si nuclear spin-echo oscillations and decay measurements on a single crystal of YbRhSi. These quantities are found to be independent from 300 K down to 
20 K, showing, however, a strong dependence below 20 K. These results indicate that electronic states near the Fermi level are modified at low temperatures. The observed spin-echo oscillations can be interpreted with the Ruderman-Kittel and pseudo-dipolar interactions between nearest-neighbor Si nuclei driven by conduction electron scattering at the Fermi surface. Possible modifications to the Fermi surface at low temperatures are discussed.
Si NMR spin-echo decay in YbRhSiKambe, Shinsaku; Sakai, Hironori; Tokunaga, Yo; Hattori, Taisuke; Lapertot, G.*; Matsuda, Tatsuma*; Knebel, G.*; Flouquet, J.*; Walstedt, R. E.*
Journal of Physics; Conference Series, 683(1), p.012006_1 - 012006_7, 2016/02
Times Cited Count：1 Percentile：55.23(Materials Science, Multidisciplinary)By means of nuclear magnetic resonance (NMR) spin-lattice relaxation time (
) measurements on a single crystal sample YbRhSi, the magnetic excitations around quantum critical phase transition is investigated. It is revealed that the coexisting Fermi and non-Fermi states appears near the quantum critical phase transition. Such a mottled state is considered to have remained hidden in Ce and U heavy fermion compounds, owing presumably to short lifetimes for the two states. The mottled state is highly anisotropic to applied magnetic field, which is consistent with previous studies. The origin of mottled state will be discussed.
SiKambe, Shinsaku; Sakai, Hironori; Tokunaga, Yo; Lapertot, G.*; Matsuda, Tatsuma*; Knebel, G.*; Flouquet, J.*; Walstedt, R. E.*
Journal of Physics; Conference Series, 592(1), p.012085_1 - 012085_5, 2015/03
Times Cited Count：2 Percentile：60.63(Physics, Atomic, Molecular & Chemical)Recently there is renewed interest in quantum critical phase transitions (QCPT) at 
K in metallic strongly-correlated electron systems. From early experimental results, the QCPT in the Kondo-lattice compound YbRhSi is not a case of the ordinary spin density wave (SDW) instability observed in Ce-based Kondo-lattices, but a candidate for a novel locally critical case In new observations reported here, we find that coexisting, static Fermi liquid (FL) and non-Fermi liquid (NFL) states are a key feature of the QCPT in YbRhSi. Such a pair of states has remained hidden in Ce compounds, owing presumably to short lifetimes for the two states. A new scaling law for the occupation ratio of the two states is derived, and could be widely applicable to Kondo-lattice systems.
Kambe, Shinsaku; Sakai, Hironori; Tokunaga, Yo; Lapertot, G.*; Matsuda, Tatsuma*; Knebel, G.*; Flouquet, J.*; Walstedt, R. E.*
Nature Physics, 10(11), p.840 - 844, 2014/11
Times Cited Count：18 Percentile：70.71(Physics, Multidisciplinary)In new observations reported here, we find that coexisting, static Fermi liquid and non-Fermi liquid states are a key feature of the QCPT in YbRhSi. By means of nuclear magnetic resonance (NMR) spin-lattice relaxation time measurements on a single crystal sample, it is revealed that the FL and NFL states are invariant,while their relative proportion in a crossover is field dependent near the QCPT. Such a pair of states has remained hidden in Ce compounds, owing presumably to short lifetimes for the two states. A new scaling law for the occupation ratio of the two states is derived, and could be widely applicable to Kondo-lattice systems
Zn
Kaneko, Koji; Raymond, S.*; Ressouche, E.*; Lapertot, G.*; Takeuchi, Tetsuya*; Hirose, Yusuke*; Honda, Fuminori*; Onuki, Yoshichika
JPS Conference Proceedings (Internet), 3, p.011061_1 - 011061_5, 2014/06
SiKambe, Shinsaku; Sakai, Hironori; Tokunaga, Yo; Lapertot, G.*; Matsuda, Tatsuma*; Knebel, G.*; Flouquet, J.*; Walstedt, R. E.*
Physical Review B, 91(16), p.161110_1 - 161110_5, 2014/04
Times Cited Count：3 Percentile：14.55(Materials Science, Multidisciplinary)Based on Si nuclear spin-lattice relaxation time () data on a single crystal of YbRhSi, the coexisting Fermi liquid (FL) and non-Fermi liquid (NFL) states around the quantum critical phase transition have been found to be sensitive to the direction of the applied magnetic field. Augmented scaling analysis shows that the anisotropic characteristic temperature and field are roughly 10 times larger for 
than for 
, consistent with a previously obtained anisotropic phase diagram.
SiPourret, A.*; Knebel, G.*; Matsuda, Tatsuma; Lapertot, G.*; Flouquet, J.*
Journal of the Physical Society of Japan, 82(5), p.053704_1 - 053704_5, 2013/05
Times Cited Count：30 Percentile：79.18(Physics, Multidisciplinary)Si using soft X-ray angle-resolved photoemission spectroscopyYasui, Akira*; Saito, Yuji; Fujimori, Shinichi; Kawasaki, Ikuto*; Okane, Tetsuo; Takeda, Yukiharu; Lapertot, G.*; Knebel, G.*; Matsuda, Tatsuma*; Haga, Yoshinori; et al.
Physical Review B, 87(7), p.075131_1 - 075131_6, 2013/02
Times Cited Count：6 Percentile：29.20(Materials Science, Multidisciplinary)We have performed soft X-ray angle-resolved photoemission spectroscopy (ARPES) measurements on YbRhSi and clarified its three-dimensional bulk valence-band structures. The ARPES spectra have not only Yb
multiplet peaks but also a finite contribution of Yb
peaks at 15 K, corresponding to the valence fluctuating behavior in this compound. This means that Yb 4f electrons in this compound have itinerant character below the 
. We have found that dispersions of the valence bands except the vicinity of the Yb 4f bands agree better with those of the band-structure calculation of LuRhSi than those of YbRhSi within a local-density approximation. In addition, the Yb 3d-4f resonant photoemission spectra of YbRhSi strongly suggest the existence of Yb 5d electrons in the valence band. We conclude that the charge transfer from the Yb 4f state to the Yb 5d state has an important role in the formation of the valence band of YbRhSi.
Raymond, S.*; Kaneko, Koji; Hiess, A.*; Steffens, P.*; Lapertot, G.*
Physical Review Letters, 109(23), p.237210_1 - 237210_5, 2012/12
Times Cited Count：20 Percentile：70.48(Physics, Multidisciplinary)
M
asson, M.-A.*; Muranaka, Hiroshi*; Matsuda, Tatsuma; Kawai, Tomoya*; Haga, Yoshinori; Knebel, G.*; Aoki, Dai*; Lapertot, G.*; Honda, Fuminori*; Settai, Rikio*; et al.
Physica C, 470(Suppl.1), p.S536 - S538, 2010/12
Times Cited Count：4 Percentile：21.87(Physics, Applied) (T:transition metal and X:Si and Ge) with non-centrosymmetric crystal structureKawai, Tomoya*; Muranaka, Hiroshi*; Masson, M.-A.*; Shimoda, Tetsuya*; Doi, Yusuke*; Matsuda, Tatsuma; Haga, Yoshinori; Knebel, G.*; Lapertot, G.*; Aoki, Dai*; et al.
Journal of the Physical Society of Japan, 77(6), p.064716_1 - 064716_9, 2008/06
Times Cited Count：67 Percentile：89.27(Physics, Multidisciplinary)Physical properties of cerium compounds CeTX were studied on single crystals. Electrical resistivity, magnetization as well as their pressure dependence revealed that the antiferromagnetism of CeCoGe is destroyed under hydrostatic pressure above 5.4 GPa and the superconductivity appears above this pressure.
ZnKaneko, Koji; Raymond, S.*; Ressouche, E.*; Shiina, Ryosuke*; Takeuchi, Tetsuya*; Hirose, Yusuke*; Honda, Fuminori*; Onuki, Yoshichika; Lapertot, G.*
no journal, ,
no abstracts in English
SiKambe, Shinsaku; Sakai, Hironori; Tokunaga, Yo; Hattori, Taisuke; Lapertot, G.*; Matsuda, Tatsuma*; Knebel, G.*; Flouquet, J.*; Walstedt, R. E.*
no journal, ,
Have created a YbRhSi of high quality Si isotope was concentrated 52% is an NMR nucleus. As the natural abundance of Si isotope is 4%, the measurement integration time by this concentration can be reduced to about one hundredth. Using this single crystal samples, NMR spin echo decay is measured. The decay curve, normal Gauss type, in addition to the attenuation of the Lorentz type, distinct oscillation term is appeared. This is considered to be due to the RKKY interaction and quadrupole interaction. In this compound, the anisotropy of the electron system is considered to be strong. Reflecting a large anisotropy of the vibration frequency is found. Further, also seen large temperature changes at low temperature.
Tokunaga, Yo; Aoki, Dai*; Braithwaite, D.*; Knebel, G.*; Brison, J.-P.*; Pourret, A.*; Lapertot, G.*; Niu, Q.*; Valiska, M.*; Flouquet, J.*; et al.
no journal, ,
Recently, uniaxial stress has been found to be a remarkable tool for tuning the pairing strength in a ferromagnetic superconductor URhGe. A relatively small uniaxial stress applied along the 
crystal axis changes the superconducting (SC) phase diagram significantly, merging the low-field SC and reentrant SC domes, with a large enhancement of 
. The increases both at zero field and under a field, reaching 1 K, more than twice higher than at ambient pressure. This enhancement of SC has been shown to be directly related to a change of the magnetic dimensionality, moving the system away from the Ising-type limit, which results in the rapid decrease of the 
. In this study, by means of zero-field 
Ge NMR in the ferromagnetic state, we have investigated the effects of uniaxial stress on the electronic state of URhGe.
Si (H//a)Kambe, Shinsaku; Sakai, Hironori; Tokunaga, Yo; Lapertot, G.*; Matsuda, Tatsuma*; Knebel, G.*; Flouquet, J.*; Walstedt, R. E.*
no journal, ,
NMR measurements in a single crystalYbRhSi are reported. Previously, the results for H//a have been reported, this time results for H//a are presented. As well as the case for H//c, the coexistence of Fermi and non-Fermi liquid states is observed for H//a, however, the T-and H-dependences are different from those for H//c.
SiKambe, Shinsaku; Sakai, Hironori; Tokunaga, Yo; Hattori, Taisuke; Lapertot, G.*; Matsuda, Tatsuma*; Knebel, G.*; Flouquet, J.*; Walstedt, R. E.*
no journal, ,
High-quality YbRhSi was produced by concentrating the Si isotope which is the NMR nucleus by 52%. Since the natural abundance ratio of Si isotope is about 4%, the accumulated measurement time can be shortened to about one hundredth by this concentration. Using this single crystal sample, NMR spin echo attenuation was measured. In the decay curve, in addition to the ordinary Gauss type and Lorentz type attenuation, clear vibration term appeared. This is thought to be due to RK interaction and quasi-dipolar interaction. A large temperature change was also observed at this low frequency in this frequency. This means that the Fermi surface is temperature dependent. Discuss these behaviors.
Tokunaga, Yo; Aoki, Dai*; Braithwaite, D.*; Knebel, G.*; Brison, J.-P.*; Pourret, A.*; Lapertot, G.*; Niu, Q.*; Valiska, M.*; Flouquet, J.*; et al.
no journal, ,
In this study, using a single crystal of URhGe, we performed zero-field NMR study under uniaxial stress. For all the observed NMR peaks, a successive shift toward lower frequencies has been ob- served with increasing the uniaxial stress. The behavior indicates uniform and successive change of local environments at the nuclear positions. Simultaneously, however, we have also seen a broadening of the NMR peaks with increasing the stress, in particular above 0.8 GPa, suggesting the distribution of the local environments with larger stresses.
