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arXiv · 2511.04208

Superconducting Properties on Two-dimensional Quasicrystal (Ta$_{0.95}$Cu$_{0.05}$)$_{1.6}$Te Studied with $^{125}$Te-NMR

H. Matsudaira·S. Kitagawa·K. Ishida·Y. Tokumoto·K. Tomiyama·K. Edagawa
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Abstract

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 superconductor with the SC transition temperature $T_{\mathrm{c}}$ = 0.94 K. The nuclear spin-lattice relaxation rate $1/T_1$ shows a coherence peak just below $T_{\mathrm{c}}$, followed by an exponential decrease down to 0.1 K. The overall temperature dependence of $1/T_1$ is in good agreement with an $s$-wave SC model with a SC gap slightly smaller than the BCS value. However, the coherence peak is unusually small, which may be attributable to a reduced Bogoliubov peak theoretically predicted for quasicrystals. Furthermore, $^{125}$Te-NMR spectra show almost no broadening nor shift in the SC state, suggesting that an unusual SC state such as parity mixing might be realized in the Ta$_{1.6}$Te superconductor.

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H. Matsudaira, S. Kitagawa, K. Ishida, Y. Tokumoto, K. Tomiyama, K. Edagawa. 2025-11-06. Superconducting Properties on Two-dimensional Quasicrystal (Ta$_{0.95}$Cu$_{0.05}$)$_{1.6}$Te Studied with $^{125}$Te-NMR. https://doi.org/10.1103/kyh6-vt3q

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