常圧と高圧で現れる高温超伝導のつながりを解明 ―格子の歪んだ薄膜への高圧印加により二つの超伝導領域を橋渡し―

2026-08-20 東京大学

研究成果のイメージ図：圧力印加による二層ニッケル酸化物の結晶構造変化がもたらす超伝導の増強

＜関連情報＞

• https://www.t.u-tokyo.ac.jp/press/pr2026-08-20-002
• https://www.nature.com/articles/s41563-026-02695-3

La2LnNi2O7薄膜における常圧超伝導と高圧超伝導の橋渡し Bridging ambient- and high-pressure superconductivity in La2LnNi2O7 films

Motoki Osada,Chieko Terakura,Shusaku Imajo,Jean-Baptiste Morée,Akiko Kikkawa,Masamichi Nakajima,Hsiao-Yi Chen,Yusuke Nomura,Koichi Kindo,Ryotaro Arita,Yoshinori Tokura & Atsushi Tsukazaki
Nature Materials  Published:18 August 2026
DOI:https://doi.org/10.1038/s41563-026-02695-3

Abstract

The discovery of high-critical-temperature (high-T_c) superconductivity near 80 K in bilayer nickelates under high pressure has sparked extensive studies. Whereas superconductivity exceeding 40 K was subsequently discovered at ambient pressure in compressively strained films, the relationship between ambient- and high-pressure regimes remains an open question. Here we present a systematic investigation of superconductivity in compressively strained La₂LnNi₂O₇ films (where Ln is a lanthanide) at ambient and high pressures. The normal-state resistivity at ambient pressure, revealed by suppressing the superconductivity with magnetic fields of 59 T, tends towards T² behaviour. Under high pressure in a cubic anvil cell, T_c was enhanced from 41–42 K at ambient pressure to 67–73 K at 16 GPa. On the other hand, lattice compression induced by Ln substitution, which may mimic the effects of pressure, lowers T_c. In both cases, T_c correlates with the evolution of normal-state transport between T² and T-linear behaviour, offering insight into the interplay between lattice structure and superconductivity in bilayer nickelates.