Shunsaku Kitagawa
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View article: Pressure evolution of magnetic structure and quasiparticle excitations in anisotropic frustrated zigzag chains
Pressure evolution of magnetic structure and quasiparticle excitations in anisotropic frustrated zigzag chains Open
Frustrated magnetic systems with anisotropic exchange interactions have been recognized as key platforms for discovering exotic quantum states and quasiparticles. In this study, we report the pressure evolution of magnetic structures and q…
View article: Antiferromagnetic Order and Magnetic Frustration in the Honeycomb Heavy-Fermion System Ce(Pt<sub>1−</sub><i><sub>x</sub></i>Pd<i><sub>x</sub></i>)<sub>6</sub>Al<sub>3</sub>: <sup>27</sup>Al and <sup>195</sup>Pt NMR Studies
Antiferromagnetic Order and Magnetic Frustration in the Honeycomb Heavy-Fermion System Ce(Pt<sub>1−</sub><i><sub>x</sub></i>Pd<i><sub>x</sub></i>)<sub>6</sub>Al<sub>3</sub>: <sup>27</sup>Al and <sup>195</sup>Pt NMR Studies Open
Heavy-fermion systems with magnetic frustration offer a rich platform for investigating the interplay among Kondo screening, magnetic frustration, and quantum criticality. We report comprehensive $^{27}$Al and $^{195}$Pt nuclear magnetic r…
View article: Novel spin dynamics in the superconducting state of kagomé superconductor
Novel spin dynamics in the superconducting state of kagomé superconductor Open
The kagomé lattice, characterized by its unique geometry, hosts exotic electronic structures such as Dirac points, flat bands, and van Hove singularities, which are closely linked to electronic instabilities. Recently, the AV3Sb5 family (A…
View article: Uniform electronic states and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>s</mml:mi></mml:math>-wave superconductivity in a strongly disordered high-entropy compound <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>X</mml:mi><mml:mrow><mml:mn>0.6</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mi>Pt</mml:mi></mml:mrow><mml:mrow><mml:mn>0.4</mml:mn></mml:mrow></mml:msub><mml:mi>Sb</mml:mi></mml:math> (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>X</mml:mi></mml:math> = Ru, Rh, Pd, Ir)
Uniform electronic states and -wave superconductivity in a strongly disordered high-entropy compound ( = Ru, Rh, Pd, Ir) Open
High-entropy compounds, where multiple elements occupy a single crystallographic site in a highly disordered manner, challenge conventional understandings of electronic structure based on periodicity and well-defined band dispersion. Here,…
View article: Magnetic Field Dependence of the Spin Susceptibility on Conventional <i>s</i>-wave Superconductor LaRu<sub>4</sub>P<sub>12</sub> Revealed by <sup>31</sup>P-NMR and <sup>139</sup>La-NMR
Magnetic Field Dependence of the Spin Susceptibility on Conventional <i>s</i>-wave Superconductor LaRu<sub>4</sub>P<sub>12</sub> Revealed by <sup>31</sup>P-NMR and <sup>139</sup>La-NMR Open
The magnetic field dependence of the spin part of Knight shift, which is proportional to the superconducting-state spin susceptibility, was investigated at two nuclear sites, $^{31}$P and $^{139}$La in a conventional s-wave superconductor …
View article: <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>b</mml:mi></mml:math>-axis and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>c</mml:mi></mml:math>-axis Knight shift measurements in the superconducting state on ultraclean <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mi>UTe</mml:mi></mml:mrow><mml:mn>2</mml:mn></mml:msub></mml:math> with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>T</mml:mi><mml:mi>c</mml:mi></mml:msub><mml:mo>=</mml:mo><mml:mn>2.1</mml:mn><mml:mo> </mml:mo><mml:mi mathvariant="normal">K</mml:mi></mml:mrow></mml:math>
-axis and -axis Knight shift measurements in the superconducting state on ultraclean with Open
Knight shifts along the $b$ and $c$ axes ($K_b$ and $K_c$) at two crystallographically distinct Te sites were measured down to 70 mK using $^{125}$Te nuclear magnetic resonance (NMR) on an ultraclean UTe$_2$ single crystal with a supercond…
View article: Subtle Structural Anomaly under Compression in Line-Nodal CaSb<sub>2</sub>
Subtle Structural Anomaly under Compression in Line-Nodal CaSb<sub>2</sub> Open
We report X-ray diffraction patterns and calculated electronic band structures of the Dirac line-nodal material CaSb$_2$ under pressure. Its superconducting transition temperature ($T_{\mathrm{c}}=1.7$ K) increases under pressure and reach…
View article: Intrinsic low-temperature magnetic properties on ultraclean <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mi>UTe</mml:mi></mml:mrow><mml:mn>2</mml:mn></mml:msub></mml:math> with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>T</mml:mi><mml:mi mathvariant="normal">c</mml:mi></mml:msub><mml:mo>=</mml:mo><mml:mn>2.1</mml:mn><mml:mo> </mml:mo><mml:mi mathvariant="normal">K</mml:mi></mml:math> revealed by <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Te</mml:mi><mml:mprescripts/><mml:none/><mml:mn>125</mml:mn></mml:mmultiscripts></mml:math> NMR
Intrinsic low-temperature magnetic properties on ultraclean with revealed by NMR Open
To investigate the intrinsic magnetic properties of UTe$_2$, we performed $^{125}$Te-NMR measurements on the ultra-clean single-crystalline UTe$_2$ with superconducting transition temperature $T_{\rm c}$ = 2.1~K and compared the results wi…
View article: Magnetic-Field Dependence of Paramagnetic Properties Investigated by <sup>63/65</sup>Cu-NMR on the Yb Zigzag-Chain Semiconductor YbCuS<sub>2</sub>
Magnetic-Field Dependence of Paramagnetic Properties Investigated by <sup>63/65</sup>Cu-NMR on the Yb Zigzag-Chain Semiconductor YbCuS<sub>2</sub> Open
To investigate the paramagnetic properties of YbCuS2 under magnetic fields, we have performed the 63/65Cu-nuclear magnetic resonance (NMR) measurements. The NMR spectra can be reproduced by the simulations of the three-dimensional powder p…
View article: Highly Uniform Magnetic and Electronic Environment in Non-Centrosymmetric Superconductor LaRhGe<sub>3</sub>
Highly Uniform Magnetic and Electronic Environment in Non-Centrosymmetric Superconductor LaRhGe<sub>3</sub> Open
We report the results of $^{139}$La NMR measurements in the non-centrosymmetric superconductor LaRhGe$_3$. This material crystallizes in a tetragonal structure without inversion symmetry and exhibits type-I superconductivity below 385 mK. …
View article: Lu/Se Substitution Effect on Magnetic Properties of Yb-Based Zigzag Chain Semiconductor YbCuS2
Lu/Se Substitution Effect on Magnetic Properties of Yb-Based Zigzag Chain Semiconductor YbCuS2 Open
We have investigated the changes in the magnetic properties on YbCuS2 by Lu or Se substitutions from a microscopic perspective. In general, it is expected that nonmagnetic Lu substitution dilutes the magnetic Yb3+ concentration, and that S…
View article: Pressure Evolution of Magnetic Structure and Quasiparticle Excitations in Anisotropic Frustrated Zigzag Chains
Pressure Evolution of Magnetic Structure and Quasiparticle Excitations in Anisotropic Frustrated Zigzag Chains Open
Frustrated magnetic systems with anisotropic exchange interactions have been recognized as key platforms for discovering exotic quantum states and quasiparticles. In this study, we report the pressure evolution of magnetic structures and q…
View article: Appearance of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>c</mml:mi></mml:math>-axis magnetic moment in odd-parity antiferromagnetic state in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>CeRh</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>As</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> revealed by <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>As</mml:mi><mml:mprescripts/><mml:none/><mml:mn>75</mml:mn></mml:mmultiscripts></mml:math>-NMR
Appearance of -axis magnetic moment in odd-parity antiferromagnetic state in revealed by -NMR Open
CeRh$_2$As$_2$ shows the superconducting (SC) multiphase under the $c$-axis\nmagnetic field, which is considered to originate from local inversion symmetry\nbreaking at the Ce site. We reported that the antiferromagnetic (AFM) order is\nin…
View article: Clear Reduction in Spin Susceptibility and Superconducting Spin Rotation for \(H\parallel a\) in the Early-Stage Sample of Spin-Triplet Superconductor UTe<sub>2</sub>
Clear Reduction in Spin Susceptibility and Superconducting Spin Rotation for \(H\parallel a\) in the Early-Stage Sample of Spin-Triplet Superconductor UTe<sub>2</sub> Open
We report the re-measurement of the $a$-axis spin susceptibility component in\nan early-stage sample of the spin-triplet superconductor UTe$_2$ with the\ntransition temperature of $T_{\\rm SC}$ = 1.6 K. Using Knight-shift measurements\nalo…
View article: Gapped Spin Excitation in Magnetic Ordered State on Yb-Based Zigzag Chain Compound YbAgSe<sub>2</sub>
Gapped Spin Excitation in Magnetic Ordered State on Yb-Based Zigzag Chain Compound YbAgSe<sub>2</sub> Open
We report the 77Se-nuclear magnetic resonance (NMR) results of trivalent Yb\nzigzag chain compound YbAgSe2, which is a sister compound of YbCuS2. The\n77Se-NMR spectrum was reproduced by considering two different Se sites with\nnegative Kn…
View article: Pressure evolution of the normal- and superconducting-state properties of the line-nodal material <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>CaSb</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> revealed by <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Sb</mml:mi><mml:mprescripts/><mml:none/><mml:mn>123</mml:mn></mml:mmultiscripts></mml:math> nuclear quadrupole resonance
Pressure evolution of the normal- and superconducting-state properties of the line-nodal material revealed by nuclear quadrupole resonance Open
CaSb$_2$ is the Dirac line-nodal material that exhibits a superconducting\n(SC) transition at 1.7 K. In spite of its conventional SC state at ambient\npressure, the transition temperature $T_{\\mathrm{c}}$ shows a peak structure\nagainst h…
View article: Breakdown of Kubo relation in Pt-Cu nanoparticles
Breakdown of Kubo relation in Pt-Cu nanoparticles Open
Nanoparticles were predicted to exhibit unique physical properties due to quantum size effects, but their identification remains difficult. According to Kubo's theory, the gap size is inversely correlated with both the density of states at…
View article: Investigation of the Hyperfine Coupling Constant of Locally Noncentrosymmetric Heavy-fermion Superconductor CeRh<sub>2</sub>As<sub>2</sub>
Investigation of the Hyperfine Coupling Constant of Locally Noncentrosymmetric Heavy-fermion Superconductor CeRh<sub>2</sub>As<sub>2</sub> Open
We performed $^{75}$As-NMR measurements in $H\parallel ab$ to investigate the normal-state magnetic properties of CeRh$_2$As$_2$, a recently-discovered heavy-fermion superconductor. We compared the NMR Knight shift $K$ with the magnetic su…
View article: Longitudinal Spin Fluctuations Driving Field-Reinforced Superconductivity in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>UTe</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>
Longitudinal Spin Fluctuations Driving Field-Reinforced Superconductivity in Open
Our measurements of ^{125}Te NMR relaxations reveal an enhancement of electronic spin fluctuations above μ_{0}H^{*}∼15 T, leading to their divergence in the vicinity of the metamagnetic transition at μ_{0}H_{m}≈35 T, below which field-rein…
View article: CSD 2280686: Experimental Crystal Structure Determination
CSD 2280686: Experimental Crystal Structure Determination Open
An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely availabl…
View article: CSD 2280688: Experimental Crystal Structure Determination
CSD 2280688: Experimental Crystal Structure Determination Open
An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely availabl…
View article: CSD 2280685: Experimental Crystal Structure Determination
CSD 2280685: Experimental Crystal Structure Determination Open
An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely availabl…
View article: CSD 2280689: Experimental Crystal Structure Determination
CSD 2280689: Experimental Crystal Structure Determination Open
An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely availabl…
View article: CSD 2280687: Experimental Crystal Structure Determination
CSD 2280687: Experimental Crystal Structure Determination Open
An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely availabl…
View article: Superconducting spin reorientation in spin-triplet multiple superconducting phases of UTe <sub>2</sub>
Superconducting spin reorientation in spin-triplet multiple superconducting phases of UTe <sub>2</sub> Open
Superconducting (SC) state has spin and orbital degrees of freedom, and spin-triplet superconductivity shows multiple SC phases because of the presence of these degrees of freedom. However, the observation of spin-direction rotation occurr…
View article: Gapless fermionic excitation in the antiferromagnetic state of ytterbium zigzag chain
Gapless fermionic excitation in the antiferromagnetic state of ytterbium zigzag chain Open
The emergence of charge-neutral fermionic excitations in magnetic systems is one of the unresolved issues in recent condensed matter physics. This type of excitations has been observed in various systems, such as low-dimensional quantum sp…
View article: Longitudinal spin fluctuations driving field-reinforced superconductivity in UTe$_2$
Longitudinal spin fluctuations driving field-reinforced superconductivity in UTe$_2$ Open
Our measurements of $^{125}$Te NMR relaxations reveal an enhancement of electronic spin fluctuations above $μ_0H^*\sim15$ T, leading to their divergence in the vicinity of the metamagnetic transition at $μ_0H_m\approx35$ T, below which fie…
View article: Large Reduction in the <i>a</i>-axis Knight Shift on UTe<sub>2</sub> with <i>T</i><sub>c</sub> = 2.1 K
Large Reduction in the <i>a</i>-axis Knight Shift on UTe<sub>2</sub> with <i>T</i><sub>c</sub> = 2.1 K Open
Spin susceptibility in the superconducting (SC) state was measured in the higher-quality sample of uranium-based superconductor UTe2 by using Knight-shift measurements for a magnetic field H along all three crystalline axes. In the higher-…
View article: Large Reduction in the $a$-axis Knight Shift on UTe$_2$ with $T_{\rm c}$ = 2.1 K
Large Reduction in the $a$-axis Knight Shift on UTe$_2$ with $T_{\rm c}$ = 2.1 K Open
Spin susceptibility in the superconducting (SC) state was measured in the higher-quality sample of uranium-based superconductor UTe$_2$ by using Knight-shift measurements for a magnetic field $H$ along all three crystalline axes. In the hi…
View article: Low-Temperature Magnetic Fluctuations Investigated by <sup>125</sup>Te-NMR on the Uranium-Based Superconductor UTe<sub>2</sub>
Low-Temperature Magnetic Fluctuations Investigated by <sup>125</sup>Te-NMR on the Uranium-Based Superconductor UTe<sub>2</sub> Open
To investigate the static and dynamic magnetic properties on the\nuranium-based superconductor UTe$_{2}$, we measured the NMR Knight shift $K$\nand the nuclear spin-lattice relaxation rate $1/T_{1}$ in $H \\parallel a$ by\n$^{125}$Te-NMR o…