Nayuta TAKEMORI. Superconductivity and emerging functionalities in aperiodic crystals: From quasicrystals to hyperuniform structures

Nayuta TAKEMORI, Osaka University, Tokoyama, Japan

Le résumé :

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Quasicrystals, since their discovery by Dan Shechtman, have attracted growing interest due to their unique combination of long-range order and aperiodicity. These structural features give rise to unconventional electronic states, including anomalous transport and, more recently, superconductivity. Bulk superconductivity has been experimentally confirmed in a Bergman-type Al-Mg-Zn quasicrystal (Tc = 50 mK) [1], and in the van der Waals quasicrystal TaTe1.6 (Tc = 1 K) [2]. These findings challenge conventional views of superconductivity based on translational symmetry.

I will introduce recent theoretical advances on superconductivity in quasicrystals, using real-space techniques such as Bogoliubov–de Gennes formalism and real-space dynamical mean-field theory. Our studies [3-6] predict non-BCS type superconductivity, including finite-momentum Cooper pairing and finite paramagnetic current even at zero temperature. These features offer a coherent explanation for experimental deviations from standard BCS theory, such as the reduced specific heat jump in quasicrystals.

In the second part, I will briefly introduce our recent initiative on hyperuniform aperiodic materials, based on a classification of structures proposed by Salvatore Torquato [7] that generalize the concept of order beyond periodicity and quasiperiodicity. 

[1] K. Kamiya et al., Nat. Commun. 9, 154 (2018).

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

[3] S. Sakai et al., Phys. Rev. B 95, 024509 (2017).

[4] N. Takemori et al., Phys. Rev. B 102, 115108 (2020).

[5] T. Fukushima et al., J. Phys.: Conf. Ser. 2461, 012014 (2023).

[6] T. Fukushima et al., Phys. Rev. Res. 5, 043164 (2023).

[7] S. Torquato et al., PRE 68, 041113 (2003); S. Torquato, Physics Reports 745 (2018).

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