K. Deguchi
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View article: Chemically tunable quantum magnetism on the anisotropic triangular lattice in rhenium oxyhalides
Chemically tunable quantum magnetism on the anisotropic triangular lattice in rhenium oxyhalides Open
The spin-1/2 Heisenberg antiferromagnet on an anisotropic triangular lattice (ATL) is an archetypal spin system hosting exotic quantum magnetism and dimensional crossover. However, the progress in experimental research on this field has be…
View article: Scattering Engineering for High Power Factor Semimetals Proved by Shubnikov‐de Haas Oscillation and Anisotropic Resistivity
Scattering Engineering for High Power Factor Semimetals Proved by Shubnikov‐de Haas Oscillation and Anisotropic Resistivity Open
The carrier dynamics of the ultra‐high power factor semimetal Ta 2 PdSe 6 are investigated using magnetotransport and anisotropic resistivity measurements. The magnetotransport analysis reveals a pronounced asymmetry in the mobilities of e…
View article: Universal whirling magnetic orders in non-Heisenberg Tsai-type quasicrystal approximants
Universal whirling magnetic orders in non-Heisenberg Tsai-type quasicrystal approximants Open
Magnetic orders of non-Heisenberg Tsai-type 1/1 approximant crystals (ACs) in the Au-Ga-Dy system were studied through bulk magnetization, neutron diffraction, and inelastic neutron scattering techniques. The results uncovered noncoplanar,…
View article: Anomalous magnetic transition in a disordered quasicrystal approximant with heavy-fermion nature
Anomalous magnetic transition in a disordered quasicrystal approximant with heavy-fermion nature Open
Quasicrystal approximant (CexY1-x)Cd6 (0 < x < 1) forms a network of corner-sharing octahedra. We report that (Ce0.8Y0.2)Cd6 exhibits an anomalous magnetic transition which can be classified neither into the conventional static magnetic or…
View article: Atomic structure and magnetism of the Au-Ga-Ce 1/1 approximant crystal
Atomic structure and magnetism of the Au-Ga-Ce 1/1 approximant crystal Open
We report a new Au-Ga-Ce 1/1 approximant crystal (AC) which possesses a significantly wide single-phase region of 53 - 70 at% Au and 13.6 - 15.1 at% Ce. Single crystal X-ray structural analyses reveal the existence of two types of structur…
View article: PREFACE
PREFACE Open
The discovery of quasicrystals, with high symmetry impossible for three-dimensional periodic crystals, has brought about a paradigm shift in crystallography and has completely changed the definition of crystals that have been accepted for …
View article: Bulk electronic structure of high-order quaternary approximants
Bulk electronic structure of high-order quaternary approximants Open
The bulk electronic structures of two high-order quaternary approximants of F-type icosahedral (i)-Al-Pd-TM quasicrystal: Al-Pd-Cr-Fe and Al-Pd-Mo-Fe, having similar electron to atom (e/a) ratio as i-Al-Pd-Mn quasicrystal, have been invest…
View article: Concomitant singularities of Yb-valence and magnetism at a critical lattice parameter of icosahedral quasicrystals and approximants
Concomitant singularities of Yb-valence and magnetism at a critical lattice parameter of icosahedral quasicrystals and approximants Open
Non-Fermi-liquid (NFL), a significant deviation from Fermi-liquid theory, usually emerges near an order-disorder phase transition at absolute zero. Recently, a diverging susceptibility toward zero temperature was observed in a quasicrystal…
View article: Local Quantum Fluctuations in Kondo Quasicrystal Approximant Ag–In–(Ce<i><sub>x</sub></i>Y<sub>1−</sub><i><sub>x</sub></i>)
Local Quantum Fluctuations in Kondo Quasicrystal Approximant Ag–In–(Ce<i><sub>x</sub></i>Y<sub>1−</sub><i><sub>x</sub></i>) Open
The ternary alloy Ag–In–Ce is the only Ce-based quasicrystal approximant showing the heavy fermion feature. Here, we report the physical properties of Ag–In–(CexY1−x). As the Ce concentration x is diluted by the nonmagnetic element Y, the …
View article: Enhancement of superconductivity by pressure-induced critical ferromagnetic fluctuations in UCoGe
Enhancement of superconductivity by pressure-induced critical ferromagnetic fluctuations in UCoGe Open
A $^{59}$Co nuclear quadrupole resonance (NQR) was performed on a\nsingle-crystalline ferromagnetic (FM) superconductor UCoGe under pressure. The\nFM phase vanished at a critical pressure $P_c$, and the NQR spectrum just below\n$P_c$ showe…
View article: Pressure effects on Ce-based Kondo approximant crystal
Pressure effects on Ce-based Kondo approximant crystal Open
The Ag–In–Ce alloy is an approximant crystal to a Tsai-type quasicrystal and exhibits heavy-fermion (Kondo) physics. This new type of Kondo material exhibits spin-glass ordering below the freezing temperature Tf ∼ 0.3 K at ambient pressure…
View article: Influence of substitution, nonstoichiometry and annealing-conditions on superconductivity and normal conductivity of Fe<sub>1+<i>δ</i></sub>(Te<sub>1−<i>x</i></sub><i>X<sub>x</sub></i>) (<i>X</i>=Se, S)
Influence of substitution, nonstoichiometry and annealing-conditions on superconductivity and normal conductivity of Fe<sub>1+<i>δ</i></sub>(Te<sub>1−<i>x</i></sub><i>X<sub>x</sub></i>) (<i>X</i>=Se, S) Open
Thermal evolution of resistivity, ρ(T, x), of as-prepared samples of Fe1+δTe1−xSx (δ ≈ 0, x ≤ 0.2 = solubility limit) demonstrate a granular log-in-T character within Ts < T <300K, a Kondo-like resistive contribution within Tc < T < Ts and…
View article: Discovery of superconductivity in quasicrystal
Discovery of superconductivity in quasicrystal Open
Superconductivity is ubiquitous as evidenced by the observation in many crystals including carrier-doped oxides and diamond. Amorphous solids are no exception. However, it remains to be discovered in quasicrystals, in which atoms are order…
View article: Direct observation of heterogeneous valence state in Yb-based quasicrystalline approximants
Direct observation of heterogeneous valence state in Yb-based quasicrystalline approximants Open
We study the electronic structure of Tsai-type cluster-based quasicrystalline\napproximants, Au$_{64}$Ge$_{22}$Yb$_{14}$ (AGY-I),\nAu$_{63.5}$Ge$_{20.5}$Yb$_{16}$ (AGY-II), and Zn$_{85.4}$Yb$_{14.6}$ (Zn-Yb),\nby means of photoemission spe…
View article: Discovery of Quantum-Criticality-Like Behavior in Dilute Kondo System: Ce<i><sub>x</sub></i>La<sub>1−</sub><i><sub>x</sub></i>Cu<sub>5.62</sub>Au<sub>0.38</sub>
Discovery of Quantum-Criticality-Like Behavior in Dilute Kondo System: Ce<i><sub>x</sub></i>La<sub>1−</sub><i><sub>x</sub></i>Cu<sub>5.62</sub>Au<sub>0.38</sub> Open
We report the discovery of a new type of non-Fermi liquid in CexLa1−xCu5.62Au0.38. When the Ce concentration x is decreased, the system changes into a dilute Kondo system. Its low-temperature susceptibility for \(x \lesssim 0.05\) is not d…
View article: Quantum critical behavior in magnetic quasicrystals and approximant crystals
Quantum critical behavior in magnetic quasicrystals and approximant crystals Open
The electronic states of quasicrystals are believed to be critical, neither extended nor localized. To experimentally establish such the critical state remains a formidable challenge. In the Au-Al-Yb quasicrystal, we observed quantum criti…
View article: Anticorrelation between polar lattice instability and superconductivity in the Weyl semimetal candidate <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>MoTe</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>
Anticorrelation between polar lattice instability and superconductivity in the Weyl semimetal candidate Open
The relation between the polar structural instability and superconductivity\nin a Weyl semimetal candidate MoTe2 has been clarified by finely controlled\nphysical and chemical pressure. The physical pressure as well as the chemical\npressu…
View article: Magnetic Properties of the Au-Al-Yb Approximant under Hydrostatic Pressure
Magnetic Properties of the Au-Al-Yb Approximant under Hydrostatic Pressure Open
We report on ac magnetic susceptibility measurements of the Au-Al-Yb approximant under pressure. It is known that the approximant shows unconventional quantum criticality at the critical pressure Pc ∼ 2 GPa, and further that the magnetic o…