Superconductivity induced by doping holes in the nodal-line semimetal NaAlGe

Toshiya Ikenobe; Takahiro Yamada; Daigorou Hirai; Hisanori Yamane; Zenji Hiroi

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arXiv · 2310.04040

Superconductivity induced by doping holes in the nodal-line semimetal NaAlGe

Toshiya Ikenobe·Takahiro Yamada·Daigorou Hirai·Hisanori Yamane·Zenji Hiroi

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Abstract

The nodal-line semimetals NaAlSi and NaAlGe have significantly different ground states despite having similar electronic structures: NaAlSi exhibits superconductivity below 7 K, while NaAlGe exhibits semiconductive electrical conductivity at low temperatures, indicating the formation of a pseudogap at approximately 100 K. The origin of the pseudogap in NaAlGe is unknown but may be associated with excitonic instability. We investigated hole-doping effects on the ground state in the solid solution Na(Al1-xZnx)Ge and discovered that the pseudogap is suppressed continuously with increasing Zn content, followed by the appearance of a superconducting dome with the highest transition temperature of 2.8 K. This superconductivity most likely results from excitonic fluctuations.

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Toshiya Ikenobe, Takahiro Yamada, Daigorou Hirai, Hisanori Yamane, Zenji Hiroi. 2023-10-06. Superconductivity induced by doping holes in the nodal-line semimetal NaAlGe. https://arxiv.org/abs/2310.04040

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