Reversible modulation of superconductivity in thin-film NbSe<sub>2</sub> via plasmon coupling.

Cheng, Guanghui; Lin, Meng-Hsien; Chen, Hung-Ying; Wang, Dongli; Wang, Zheyan; Qin, Wei; Zhang, Zhenyu; Zeng, Changgan · Nat Commun · 2024

basic_science · Level V

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Abstract

In recent years, lightwave has stood out as an ultrafast, non-contact control knob for developing compact superconducting circuitry. However, the modulation efficiency is limited by the low photoresponse of superconductors. Plasmons, with the advantages of strong light-matter interaction, present a promising route to overcome the limitations. Here we achieve effective modulation of superconductivity in thin-film NbSe<sub>2</sub> via near-field coupling to plasmons in gold nanoparticles. Upon resonant plasmon excitation, the superconductivity of NbSe<sub>2</sub> is substantially suppressed. The modulation factor exceeds 40% at a photon flux of 9.36 × 10<sup>13 </sup>s<sup>-1</sup>mm<sup>-2</sup>, and the effect is significantly diminished for thicker NbSe<sub>2</sub> samples. Our observations can be theoretically interpreted by invoking the non-equilibrium electron distribution in NbSe<sub>2</sub> driven by the plasmon-associated evanescent field. Finally, a reversible plasmon-driven superconducting switch is realized in this system. These findings highlight plasmonic tailoring of quantum states as an innovative strategy for superconducting electronics.