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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
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:10 Percentile:82.13(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:33 Percentile:95.03(Materials Science, Multidisciplinary)Kambe, 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:17.22(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.
Kambe, 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:55.6By 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.
Kambe, 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:61.05Recently 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:71.17(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
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
Kambe, 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:14.77(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.
Pourret, 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:29 Percentile:78.94(Physics, Multidisciplinary)Yasui, 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:29.47(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:19 Percentile:70.77(Physics, Multidisciplinary)Masson, 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:22.02(Physics, Applied)Kawai, 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:65 Percentile:89.2(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.
Kambe, Shinsaku; Tokunaga, Yo; Sakai, Hironori; Matsuda, Tatsuma; Haga, Yoshinori; Lapertot, G.*; Aoki, Dai*; Flouquet, J.*; Brison, J. P.*
no journal, ,
NMR study of single crystal YbRhSi are performed. A high quality single crystal of 52% Si enriched sample is made. Owing to this enrichment, S/N is improved 100 times. spin-lattice relaxation, spin-spin relaxation and Knight shift have been determined as a function of T and direction of magnetic field of 7.2T. Below 6K, the Fermi-liquid behavior has been observed for H//a which is consistent with the previous data be Ishida et al. Behavior for H//c is quite different comparing with that for H//a.
Kambe, Shinsaku; Tokunaga, Yo; Sakai, Hironori; Matsuda, Tatsuma; Haga, Yoshinori; Lapertot, G.*; Aoki, Dai*; Flouquet, J.*; Brison, J. P.*
no journal, ,
We have made 52% Si isotope enriched high quality single crystal sample of YbRhSi. Since the natural abundance of Si is only 4%, we can improve S/N of NMR signal by 100 times using this enriched sample. Spin-lattice relaxation time T is measured. In this compound, the QCP is appeared at 0.66T for H//c, 0.06T for H//a. At first, measurements are performed at 7.2T in the Fermi-liquid state. A crossover to the Fermi-liquid state is observed below 6K for H//a as previous report. The behavior for H//c is different.
Yasui, Akira; Fujimori, Shinichi; Kawasaki, Ikuto; Okane, Tetsuo; Takeda, Yukiharu; Saito, Yuji; Lapertot, G.*; Knebel, G.*; Matsuda, Tatsuma; Haga, Yoshinori; et al.
no journal, ,
In recent years, YbRhSi has been attracted much attention because it can be turned through a quantum critical point (QCP) by various small changes of control parameters. There are many angle-resolved photoemission spectroscopy (ARPES) studies for YbRhSi by using low-energy incident photons to understand the nature of the QCP. However, large surface contributions were observed in their spectra, and its bulk electronic structure has not been understood experimentally. We have performed the soft X-ray ARPES for YbRhSi to obtain its bulk valence-band structure. Obtained valence-band structure is similar to the calculated result of LuRhSi within a local-density approximation, while the Yb 4 bands are observed near Fermi level and are hybridized with conduction bands.
Yasui, Akira; Fujimori, Shinichi; Kawasaki, Ikuto; Okane, Tetsuo; Takeda, Yukiharu; Saito, Yuji; Lapertot, G.*; Knebel, G.*; Matsuda, Tatsuma; Haga, Yoshinori; et al.
no journal, ,
In recent years, YbRhSi has been attracted much attention because it can be turned through a quantum critical point (QCP) by various small changes of control parameters. Many studies on its electronic structure have been performed for this compound to understand the nature of the QCP, but its bulk electronic structure has not been understood. Experimental observations of the valence-band structure including Yb 4 bands are needed to establish the theoretical model which describes the electronic structure of YbRhSi correctly. We have performed the soft X-ray angle-resolved photoemission spectroscopy for YbRhSi to obtain its bulk valence-band structure. Experimental valence-band structure is similar to the calculated result of LuRhSi within a local-density approximation, while the Yb 4 bands are observed near Fermi level.
Yasui, Akira; Fujimori, Shinichi; Kawasaki, Ikuto; Okane, Tetsuo; Takeda, Yukiharu; Saito, Yuji; Lapertot, G.*; Knebel, G.*; Matsuda, Tatsuma; Haga, Yoshinori; et al.
no journal, ,
no abstracts in English
Kaneko, Koji; Raymond, S.*; Hiess, A.*; Fk, B.*; Steffens, P.*; Lapertot, G.*; Settai, Rikio*; Onuki, Yoshichika
no journal, ,