Yuki Tokumoto
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View article: Superconducting Properties on Two-dimensional Quasicrystal (Ta$_{0.95}$Cu$_{0.05}$)$_{1.6}$Te Studied with $^{125}$Te-NMR
Superconducting Properties on Two-dimensional Quasicrystal (Ta$_{0.95}$Cu$_{0.05}$)$_{1.6}$Te Studied with $^{125}$Te-NMR Open
Physical properties in the normal and superconducting (SC) state are investigated with $^{125}$Te-nuclear magnetic resonance (NMR) measurements in a quasicrystal $\mathrm{(Ta_{0.95}Cu_{0.05})_{1.6}Te}$, which was a recently discovered supe…
View article: Microwave-driven adsorption-desorption for NOx removal: A simplistic approach
Microwave-driven adsorption-desorption for NOx removal: A simplistic approach Open
View article: Visualization of spin-polarized surface resonances in Pb-based ternary topological insulators
Visualization of spin-polarized surface resonances in Pb-based ternary topological insulators Open
View article: Large Rashba spin-orbit coupling in metallic SrTaO<sub>3</sub> thin films
Large Rashba spin-orbit coupling in metallic SrTaO<sub>3</sub> thin films Open
We fabricated conductive SrTaO 3 epitaxial films on insulator substrates and measured Rashba parameter using weak anti-localization analysis. The Rashba parameter, reaching up to 9.9×10 -13 eVm, is the highest among metallic oxides and is …
View article: Anomalous upper critical field in the quasicrystal superconductor Ta1.6Te
Anomalous upper critical field in the quasicrystal superconductor Ta1.6Te Open
Superconductivity in quasicrystals poses a new challenge in condensed matter physics. We measured the resistance and ac magnetic susceptibility of a Ta 1.6 Te dodecagonal quasicrystal, which is superconducting below T c ~ 1 K. We show that…
View article: Large Rashba spin-orbit coupling in metallic SrTaO$_3$ thin films
Large Rashba spin-orbit coupling in metallic SrTaO$_3$ thin films Open
Epitaxial thin films of SrTaO$_3$ with thickness ($t$) smaller than 74 nm were successfully fabricated on an insulator (LaAlO$_3$)$_{0.3}$(Sr$_2$AlTaO$_6$)$_{0.7}$ substrate. Films with $t$ above 8.6 nm showed metallic conduction. Both con…
View article: Superconductivity in a van der Waals layered quasicrystal
Superconductivity in a van der Waals layered quasicrystal Open
View article: Anomalous upper critical field in the quasicrystal superconductor Ta$_{1.6}$Te
Anomalous upper critical field in the quasicrystal superconductor Ta$_{1.6}$Te Open
Superconductivity in quasicrystals poses a new challenge in condensed matter physics. We measured the resistance and ac magnetic susceptibility of a Ta$_{1.6}$Te dodecagonal quasicrystal, which is superconducting below $T_c \sim$ 1 K. We s…
View article: Unraveling the effects of phason strain on the thermoelectric properties in Ag-In-Yb icosahedral quasicrystals
Unraveling the effects of phason strain on the thermoelectric properties in Ag-In-Yb icosahedral quasicrystals Open
This study represents the experimental comparative analysis of the thermoelectric properties in an Ag-In-Yb phason-free icosahedral quasicrystal (iQC) and four phason-strained iQCs. The aim is to understand how phason strain affects these …
View article: Superconductivity in a van der Waals layered quasicrystal
Superconductivity in a van der Waals layered quasicrystal Open
van der Waals (vdW) layered transition-metal chalcogenides are attracting significant attention owing to their fascinating physical properties. This group of materials consists of abundant members with various elements, having a variety of…
View article: Topological surface states hybridized with bulk states of Bi-doped PbSb2Te4 revealed in quasiparticle interference
Topological surface states hybridized with bulk states of Bi-doped PbSb2Te4 revealed in quasiparticle interference Open
Topological surface states of Bi-doped PbSb2Te4 [Pb(Bi0.20Sb0.80)2Te4] are investigated through analyses of quasiparticle interference (QPI) patterns observed by scanning tunneling microscopy. Interpretation of the experimental QPI pattern…
View article: Experimental verification of band convergence in Sr and Na codoped PbTe
Experimental verification of band convergence in Sr and Na codoped PbTe Open
Scanning tunneling microscopy and transport measurements have been performed to investigate the electronic structure and its temperature dependence in heavily Sr and Na codoped PbTe, which is recognized as one of the most promising thermoe…
View article: Phonon–Phason Coupling Strength in a Tsai-Type Ag–In–Yb Icosahedral Quasicrystal
Phonon–Phason Coupling Strength in a Tsai-Type Ag–In–Yb Icosahedral Quasicrystal Open
Owing to the quasiperiodic order, one independent term in the elasticity of quasicrystals (phonon–phason coupling) is characteristic of quasicrystals. It is not seen in conventional crystals and has continued to be a significant subject in…
View article: Evaluating the phonon-phason coupling strength of an Al-Ni-Co decagonal quasicrystal
Evaluating the phonon-phason coupling strength of an Al-Ni-Co decagonal quasicrystal Open
Recently, a novel method was proposed to probe the phonon-phason coupling effect in quasicrystals, and it was applied to an Al-Pd-Mn icosahedral quasicrystal. In this study, the method was applied to an Al-Ni-Co decagonal quasicrystal with…
View article: Unraveling the Effects of Phason Strain on the Thermoelectric Properties in Ag-in-Yb Icosahedral Quasicrystals
Unraveling the Effects of Phason Strain on the Thermoelectric Properties in Ag-in-Yb Icosahedral Quasicrystals Open
View article: Direct experimental evidence of phonon–phason coupling in an Al-Pd-Mn icosahedral quasicrystal
Direct experimental evidence of phonon–phason coupling in an Al-Pd-Mn icosahedral quasicrystal Open
Due to their unique structural order, quasicrystals have special elastic degrees of freedom called the phason degrees of freedom, in addition to the conventional phonon degrees of freedom. In this study, we demonstrate the presence of phon…
View article: Comparative study of high-temperature specific heat for Al–Pd–Mn icosahedral quasicrystals and crystal approximants
Comparative study of high-temperature specific heat for Al–Pd–Mn icosahedral quasicrystals and crystal approximants Open
Quasicrystals (QCs) have a peculiar structural order characterized by quasiperiodicity and non-crystallographical point group symmetry. To reveal their characteristic physical property reflecting the peculiar structural order, specific hea…
View article: High-Temperature Specific Heat of Al–Cu–Ru Icosahedral Quasicrystals and 1/1 Crystal Approximants
High-Temperature Specific Heat of Al–Cu–Ru Icosahedral Quasicrystals and 1/1 Crystal Approximants Open
We report the results of specific heat measurements for Al–Cu–Ru icosahedral quasicrystals (i-QCs) and 1/1 crystal approximants (1/1-CAs) in the temperature range from 350 to 1250 K. The i-QCs and 1/1-CAs showed a marked upward deviation o…
View article: Evidences of inner Se ordering in topological insulator PbBi2Te4-PbBi2Se4-PbSb2Se4 solid solutions
Evidences of inner Se ordering in topological insulator PbBi2Te4-PbBi2Se4-PbSb2Se4 solid solutions Open
In topological insulators (TIs), carriers originating from non-stoichiometric defects hamper bulk insulation. In (Bi,Sb) 2 (Te,Se) 3 TIs (BSTS TIs), however, Se atoms strongly prefer specific atomic sites in the crystal structure (Se order…
View article: Conductive and Non-conductive Dislocations in Bi–Sb Topological Insulators
Conductive and Non-conductive Dislocations in Bi–Sb Topological Insulators Open
Electrical resistivity measurements were performed for plastically deformed Bi–Sb topological insulators to investigate the formation of one-dimensional gapless states along dislocations, which has been previously discussed theoretically. …
View article: High-Density Well-Aligned Dislocations Introduced by Plastic Deformation in Bi1−xSbx Topological Insulator Single Crystals
High-Density Well-Aligned Dislocations Introduced by Plastic Deformation in Bi1−xSbx Topological Insulator Single Crystals Open
Topological insulators (TIs) have a bulk bandgap and gapless edge or surface states that host helically spin-polarized Dirac fermions. Theoretically, it has been predicted that gapless states could also be formed along dislocations in TIs.…
View article: Optimizing composition of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>Pb</mml:mi><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mi mathvariant="normal">B</mml:mi><mml:msub><mml:mi mathvariant="normal">i</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:mi mathvariant="normal">S</mml:mi><mml:msub><mml:mi mathvariant="normal">b</mml:mi><mml:mi>x</mml:mi></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:mi mathvariant="normal">T</mml:mi><mml:msub><mml:mi mathvariant="normal">e</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math> topological insulator to achieve a bulk-insulating state
Optimizing composition of topological insulator to achieve a bulk-insulating state Open
A series of $\mathrm{Pb}{(\mathrm{B}{\mathrm{i}}_{1\ensuremath{-}x}\mathrm{S}{\mathrm{b}}_{x})}_{2}\mathrm{T}{\mathrm{e}}_{4}$ topological-insulator crystals with various Sb molar ratios $x$ was fabricated, and a systematic study of their …
View article: Fabrication of full-color GaN-based light-emitting diodes on nearly lattice-matched flexible metal foils
Fabrication of full-color GaN-based light-emitting diodes on nearly lattice-matched flexible metal foils Open
View article: Dislocation conduction in Bi-Sb topological insulators
Dislocation conduction in Bi-Sb topological insulators Open
Previous theoretical works have predicted that when a specific condition is satisfied, dislocations in three-dimensional topological insulators form one-dimensional gapless states, which are topologically protected against disorder scatter…
View article: Elastic properties of indium nitrides grown on sapphire substrates determined by nano-indentation: In comparison with other nitrides
Elastic properties of indium nitrides grown on sapphire substrates determined by nano-indentation: In comparison with other nitrides Open
The hardness of wurtzite indium nitride (α-InN) films of 0.5 to 4 μm in thickness was measured by the nano-indentation method at room temperature. After investigation of crystalline quality by x-ray diffraction, the hardness and Young’s mo…