The spinel-type ${\mathrm{LiV}}_2{\mathrm{O}}_4$ exhibits heavy-fermion metallic behaviors at low temperatures, but the effect of composition modulation on them is unknown. We realized the epitaxial growth of highly crystalline ${\mathrm{LiV}}_2{\mathrm{O}}_4$ films and conducted the electrochemical Li-ion intercalation (electron doping) to investigate systematic variation of transport properties in ${\mathrm{Li}}_{1+x}{\mathrm{V}}_2{\mathrm{O}}_4$. We found that adjustment of Li content during pulsed-laser deposition was important to obtain films exhibiting the heavy-fermion metallic behavior comparable to that of a bulk single crystal. At low doping regime $(x\le 0.5)$, resistivity increased with increasing electron filling. The slope of their linear $T^2$ dependence also increased in accordance of a Fermi-liquid model. At high doping regime $\left(x>0.5\right)$, a Mott transition was observed over a range of Li content where a new spinel phase and the original one coexisted. The results revealed that the electron doping induced enhancement of the electron correlation and the resultant Mott transition.

中文翻译：

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LiV2O4外延薄膜中锂离子嵌入诱导的重费米子金属态和莫特跃迁

尖晶石型 ${\mathrm{锂离子电池}}_2{\mathrm{哦}}_4$在低温下表现出重费米子金属行为，但成分调制对它们的影响尚不清楚。我们实现了高结晶度的外延生长${\mathrm{锂离子电池}}_2{\mathrm{哦}}_4$ 薄膜并进行电化学锂离子嵌入（电子掺杂）以研究传输特性的系统变化 ${李}_{1+X}{\mathrm{伏}}_2{\mathrm{哦}}_4$. 我们发现在脉冲激光沉积过程中调整锂含量对于获得具有与块状单晶相当的重费米子金属行为的薄膜很重要。在低掺杂状态下$(X\le 0.5)$，电阻率随着电子填充的增加而增加。它们的线性斜率${吨}^2$根据费米液体模型，依赖性也增加了。在高兴奋剂情况下$\left(X>0.5\right)$，在新的尖晶石相和原始相共存的锂含量范围内观察到莫特转变。结果表明，电子掺杂诱导了电子相关性的增强和由此产生的莫特跃迁。