Conventional BCS theory relies on translational symmetry to explain superconductivity (SC). Therefore, the discovery of bulk SC in the Al-Mg-Zn quasicrystal (QC) in 2018 presented a fundamental question: how can Cooper pairs form in a system without translational symmetry? While Al-Mg-Zn brought us a breakthrough, its extremely low transition temperature (T_c ~ 50 mK) prevented detailed microscopic investigations.

Recently, bulk SC with T_c near 1 K was reported in the dodecagonal van der Waals QC Ta_1.6Te family [1], which provides a unique opportunity to investigate quasicrystalline superconducting properties in depth. Here, we report ¹²⁵Te-NMR measurements on polycrystalline ()_1.6 Te ( K) [2]. The nuclear spin–lattice relaxation rate, 1/T₁, exhibits a small coherence peak just below T_c, followed by an exponential decrease at lower temperatures. This behavior is consistent with a fully gapped s-wave state. The unusually suppressed coherence peak suggests that the quasicrystalline structure smears the divergence of the quasiparticle density of states. We will discuss the implications of these results, regarding the influence of quasiperiodicity in the superconducting state.

[1] Y. Tokumoto et al., Nat. Commun. 15, 1529 (2024).

[2] H. Matsudaira et al., arXiv : 2511.04208.