We report a systematic elastoresistivity study on ${\mathrm{LaFe}}_{1-x}{\mathrm{Co}}_x\mathrm{AsO}$ single crystals, which have well separated structural and magnetic transition lines. All crystals show a Curie-Weiss–like nematic susceptibility in the tetragonal phase. The extracted nematic temperature is monotonically suppressed upon cobalt doping, and changes sign around the optimal doping level, indicating a possible nematic quantum critical point beneath the superconducting dome. The amplitude of the nematic susceptibility shows a peculiar double-peak feature. This could be explained by a combined effect of different contributions to the nematic susceptibility, which are amplified at separated doping levels of ${\mathrm{LaFe}}_{1-x}{\mathrm{Co}}_x\mathrm{AsO}$.

中文翻译：

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LaFe_ {1-x} Co_ {x} AsO中向列磁化率的演变。

我们报告了关于 ${\mathrm{镧铁}}_{\mathrm{1个}-X}{\mathrm{有限公司}}_X\mathrm{AsO}$具有完全分离的结构和磁性过渡线的单晶。所有晶体在四方相中都显示出居里-魏斯样的向列磁化率。提取的向列温度在钴掺杂后被单调抑制，并且在最佳掺杂水平附近改变符号，表明超导圆顶下方可能存在向列量子临界点。向列磁化率的振幅显示出独特的双峰特征。这可以通过对向列磁化率的不同贡献的综合效应来解释，该贡献在单独的掺杂水平下被放大。${\mathrm{镧铁}}_{\mathrm{1个}-X}{\mathrm{有限公司}}_X\mathrm{AsO}$。