桥接La$_2$LnNi$_2$O$_7$薄膜的常压与高压超导电性
Bridging ambient- and high-pressure superconductivity in La$_2$LnNi$_2$O$_7$ films
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中文总结 AI 辅助
本文研究La$_2$LnNi$_2$O$_7$薄膜常压与高压超导电性，发现$T_{\text{c}}$随压力升高而提升、随Ln取代诱导的晶格压缩而降低，揭示其与正常态输运行为演化的关联。
中文摘要 AI 辅助
高压下层状镍氧化物中发现近80 K的高临界温度$T_{\text{c}}$超导电性后引发广泛研究，后续在压缩应变薄膜中发现常压下超导电性超过40 K，但常压与高压区间的关联仍是未解决问题。本文系统研究压缩应变La$_2$LnNi$_2$O$_7$薄膜（Ln为镧系元素）在常压与高压下的超导电性：通过59 T磁场抑制超导电性揭示的常压正常态电阻率趋近$T^2$行为；在立方对砧高压装置中，$T_{\text{c}}$从常压下的41-42 K提升至16 GPa下的67-73 K；另一方面，Ln取代诱导的晶格压缩（可模拟压力效应）会降低$T_{\text{c}}$。两种情况下，$T_{\text{c}}$与正常态输运在$T^2$和$T$线性行为间的演化相关，为理解层状镍氧化物中晶格结构与超导电性的相互作用提供了线索。
英文摘要
The discovery of high critical-temperature $T_{\mathrm{c}}$ superconductivity near 80 K in bilayer nickelates under high pressure has sparked extensive studies. While 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 La$_2$LnNi$_2$O$_7$ films (Ln = lanthanides) at ambient and high pressures. The normal-state resistivity at ambient pressure, revealed by suppressing superconductivity with magnetic fields of 59 T, tends toward $T^2$ behaviour. Under high pressure in a cubic-anvil cell, $T_{\mathrm{c}}$ 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 effects of pressure, lowers $T_{\mathrm{c}}$. In both cases, $T_{\mathrm{c}}$ correlates with the evolution of normal-state transport between $T^2$ and $T$-linear behaviour, offering insight into the interplay between lattice structure and superconductivity in bilayer nickelates.
