Article
Physics, Multidisciplinary
J. Maklar, M. Schuler, Y. W. Windsor, C. W. Nicholson, M. Puppin, P. Walmsley, I. R. Fisher, M. Wolf, R. Ernstorfer, M. A. Sentef, L. Rettig
Summary: In this study, we investigate the relaxation dynamics in the charge-density-wave (CDW) system TbTe3 after ultrafast optical excitation using both experimental and theoretical methods. We observe an unusual transient modulation of the relaxation rates of excited photocarriers through time- and angle-resolved photoemission spectroscopy. A detailed analysis of the electron self-energy based on a nonequilibrium Green's function formalism provides a microscopic understanding of the observed dynamics and reveals the impact of the electronic band structure on the self-energy.
PHYSICAL REVIEW LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Daniel Shaffer, Jian Wang, Luiz H. Santos
Summary: The study investigates mean-field states resulting from electron pairing in Hofstadter bands and describes a Ginzburg-Landau theory for thermodynamic properties of Hofstadter superconductors. Different symmetry breaking patterns of the MTG are identified in a rich phase diagram, with a focus on 96q-symmetric Hofstadter SCs. Topological properties of these systems are studied with an established novel topological invariant capturing the existence of charge-neutral gapless excitations.
Article
Thermodynamics
M. Gnaneswara Reddy, K. Ganesh Kumar
Summary: This research explores the significance of C-C heat flux on carbon nanotubes embedded with micropolar liquid over a melting surface, converting the model to a set of ordinary differential equations for analysis of its impact on energy and velocity. The study reveals non-uniform flow and thermal boundary layers for SWCNT/MWCNT, with larger material parameter scale reducing velocity and angular velocity. Additionally, streamline analysis is presented.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Engineering, Electrical & Electronic
Kazuhito Asai, Naoki Takeuchi, Hideo Suzuki, Yuki Yamanashi, Nobuyuki Yoshikawa
Summary: This study investigates the transmission line effects of a long gate-to-gate interconnection in AQFP logic circuits. Reflection effects in a long transmission line between AQFP gates were observed, and a damping resistance was adopted to stabilize the reflection effect. Circuit simulations confirmed that a damping resistance connected in parallel to the transmission line effectively stabilizes the reflection effect, enabling an interconnection length longer than 1 mm.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2022)
Article
Physics, Multidisciplinary
Aki Kitaori, Naoya Kanazawa, Takanori Kida, Yasuo Narumi, Masayuki Hagiwara, Koichi Kindo, Tetsuya Takeuchi, Ai Nakamura, Dai Aoki, Yoshinori Haga, Yoshio Kaneko, Yoshinori Tokura, Yoshichika O. Nuki
Summary: We have successfully grown single crystalline Tb5Sb3 with a hexagonal structure, which exhibits complex spiral magnetic structures with changing temperature. Specific heat and magnetization measurements revealed one clear magnetic transition at 133 K. The magnetic structure is oriented in the hexagonal basal plane with a hard axis corresponding to the [0001] direction. Below 50 K, the magnetic structure undergoes a transformation, leading to a rapid decrease in magnetic susceptibility for H II [1010] and a kink behavior in low-field magnetization, while showing hysteresis in the magnetization curve.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2023)
Article
Physics, Multidisciplinary
Petr Opletal, Hironori Sakai, Yoshinori Haga, Yoshifumi Tokiwa, Etsuji Yamamoto, Shinsaku Kambe, Yo Tokunaga
Summary: We studied the physical properties of a single crystal of uranium telluride U7Te12. It was found that U7Te12 crystallizes in a hexagonal structure with three different crystallographic uranium sites. The paramagnetic moments were estimated to be approximately 1 µB per uranium site assuming a uniform moment on all the sites. A ferromagnetic phase transition occurred at TC = 48 K, with a sharp increase in in-plane magnetization while the out-of-plane component did not increase significantly. Further below TC under field-cooling conditions, the out-of-plane component increased rapidly around T* = 26 K, while the in-plane component showed little change at T*. Specific heat measurement indicated a crossover suggesting a reorientation of ordering moments or successive magnetic ordering of the multiple uranium sites.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2023)
Article
Physics, Multidisciplinary
H. Sakai, Y. Tokiwa, P. Opletal, M. Kimata, S. Awaji, T. Sasaki, D. Aoki, S. Kambe, Y. Tokunaga, Y. Haga
Summary: The superconducting phase diagram in uranium ditelluride was investigated using high-quality single crystals under magnetic fields along the hard magnetic b axis. Low-field and high-field superconducting phases with different field-angular dependence were distinguished through electrical resistivity and ac magnetic susceptibility measurements. The crystal quality affected the upper critical field of the low-field superconducting phase, but the H* value at which the high-field superconducting phase appeared remained the same across different crystals. A phase boundary signature was also observed inside the low-field superconducting phase near H*, indicating the presence of an intermediate superconducting phase characterized by small flux pinning forces.
PHYSICAL REVIEW LETTERS
(2023)
Article
Multidisciplinary Sciences
Kota Ishihara, Masaki Roppongi, Masayuki Kobayashi, Kumpei Imamura, Yuta Mizukami, Hironori Sakai, Petr Opletal, Yoshifumi Tokiwa, Yoshinori Haga, Kenichiro Hashimoto, Takasada Shibauchi
Summary: Evidence consistent with chiral B-3u+iA(u) spin-triplet superconductivity in UTe2 is found through magnetic penetration depth measurements.
NATURE COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Tomoya Asaba, Lang Peng, Takahiro Ono, Satoru Akutagawa, Ibuki Tanaka, Hinako Murayama, Shota Suetsugu, Aleksandar Razpopov, Yuichi Kasahara, Takahito Terashima, Yuhki Kohsaka, Takasada Shibauchi, Masatoshi Ichikawa, Roser Valenti, Shin-ichi Sasa, Yuji Matsuda
Summary: We have discovered a simple method to fabricate atomic-scale wires with various arrangements, including stripes, X-junctions, Y-junctions, and nanorings. These wires are grown on graphite substrates by pulsed-laser deposition and have precise dimensions. Our findings suggest that nonequilibrium reaction-diffusion processes are crucial for the formation of atomic patterns, and this discovery opens up new possibilities for constructing quantum networks at the atomic scale.
Article
Multidisciplinary Sciences
M. Culo, S. Licciardello, K. Ishida, K. Mukasa, J. Ayres, J. Buhot, Y. T. Hsu, S. Imajo, M. W. Qiu, M. Saito, Y. Uezono, T. Otsuka, T. Watanabe, K. Kindo, T. Shibauchi, S. Kasahara, Y. Matsuda, N. E. Hussey
Summary: The authors present high-field magnetotransport measurements of FeSe1-xSx and FeSe1-xTex, which show a broad quantum vortex liquid regime. This indicates the presence of a quantum vortex liquid state and the destruction of the Abrikosov lattice by intense quantum fluctuations at very low temperatures.
NATURE COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Kyugo Ota, Yuki Watabe, Yoshinori Haga, Fabio Iesari, Toshihiro Okajima, Yuji Matsumoto
Summary: Asymmetry plays an important role in discovering new phenomena, and the honeycomb structure is an example of asymmetric structure. The crystal structure analysis of Ce2Pt6Al15 is difficult due to stacking disorder, but we successfully synthesized polycrystalline Ce2Pt6Al15 and single-crystalline Ce2Pt6Al15. The analysis of the samples confirmed the trivalent valence of Ce in Ce2Pt6Al15 and revealed an orthorhombic structure with honeycomb structure.
Article
Physics, Multidisciplinary
Yuta Mizukami, Masahiro Haze, Ohei Tanaka, Kohei Matsuura, Daiki Sano, Jakob Boeker, Ilya Eremin, Shigeru Kasahara, Yuji Matsuda, Takasada Shibauchi
Summary: The authors use FeSe1-xSx to investigate the evolution of the superconducting state in the BCS-BEC crossover regime and observe the multiband nature of the crossover, as well as a suppression of the nematic order upon S-substitution. Recent experiments suggest that investigations into the BCS-BEC crossover may be possible using strongly correlated systems, in addition to ultracold atomic systems.
COMMUNICATIONS PHYSICS
(2023)
Article
Physics, Multidisciplinary
Zhongyu Yu, Koya Nakamura, Kazuya Inomata, Xiaoling Shen, Taketora Mikuri, Kohei Matsuura, Yuta Mizukami, Shigeru Kasahara, Yuji Matsuda, Takasada Shibauchi, Yoshiya Uwatoko, Naoki Fujiwara
Summary: The study of FeSe has led to the discovery of spin fluctuations originating from Bogoliubov Fermi surfaces in the superconducting state.
COMMUNICATIONS PHYSICS
(2023)
Article
Physics, Multidisciplinary
K. Ishihara, M. Kobayashi, K. Imamura, M. Konczykowski, H. Sakai, P. Opletal, Y. Tokiwa, Y. Haga, K. Hashimoto, T. Shibauchi
Summary: The exotic superconducting properties of the paramagnetic spin-triplet superconductor candidate UTe2, such as extremely high upper critical field and possible chiral superconducting states, have attracted significant attention. This study focuses on the thermodynamic critical field Hc, the lower critical field Hc1, and the upper critical field Hc2 at low fields of ultraclean single crystals of UTe2, providing crucial insight into its intrinsic superconducting properties. Anomalous enhancement of Hc1 values with magnetic field along the b and c axes, showing unusual low-temperature upturns, is attributed to the effect of strong Ising-like ferromagnetic fluctuations on the vortex line energy.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
Elina Zhakina, Philippa H. McGuinness, Markus Koenig, Romain Grasset, Maja D. Bachmann, Seunghyun Khim, Carsten Putzke, Philip J. W. Moll, Marcin Konczykowski, Andrew P. Mackenzie
Summary: High-energy electron irradiation is used to study the effects on PtCoO2, and it is found that this technique can transition from nonlocal to local transport behavior, thus determining the nature and extent of unconventional transport regimes.
Article
Materials Science, Multidisciplinary
Yukiharu Takeda, Jiri Pospisil, Hiroshi Yamagami, Etsuji Yamamoto, Yoshinori Haga
Summary: The element-specific electronic states and magnetic properties of UCoGe and Ru-substituted U(Co0.88Ru0.12)Ge were investigated using soft x-ray magnetic circular dichroism experiments. The results show that the Co 3d electrons play an important role in these compounds.
Article
Materials Science, Multidisciplinary
Ikuto Kawasaki, Kazuharu Takeuchi, Shin-ichi Fujimori, Yukiharu Takeda, Hiroshi Yamagami, Etsuji Yamamoto, Yoshinori Haga
Summary: Angle-resolved photoemission spectroscopy (ARPES) experiments were performed to investigate the electronic structure of the heavy-fermion superconductor UPt3. The band structure of UPt3 was compared with density-functional calculations for ThPt3, and it was found that ThPt3 calculations provided a better description of the experimental band structure except for the heavy quasiparticle bands derived from 5f orbitals. The heavy quasiparticle bands were found to be renormalized by electron correlation effects and showed little temperature dependence.
