We performed an ultrasonic measurement for the heavy-fermion compound CeRhIn${}_5$ to investigate the origin of the field-induced anisotropic phase in high magnetic fields. The transverse elastic constant $C_T=(C_{11}-C_{12})/2$ and the ultrasonic attenuation coefficient ${\alpha }_T$ show clear anomaly at $B^{\star }=28.5$ T, which was discussed as the electronic nematic transition point. In addition, $C_T$ exhibits acoustic de Haas-van Alphen oscillation below 28.5 T. These elastic anomalies around $B^{\star }$ indicate an electric quadrupole ordering of $O_{x^2-y^2}$ accompanied by $B_{1}g$ crystal symmetry breaking and Fermi surface reconstruction due to the quadrupole-strain coupling, which results from itinerant $4f$ electrons and the $p$-$f$ hybridized state.

中文翻译：

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CeRhIn5中四极有序和晶体对称性破裂的高场超声研究

我们对重金属化合物CeRhIn进行了超声波测量${}_5$研究高磁场中场感应各向异性相的起源。横向弹性常数$C_{Ť}=（C_{11}-C_{12}）/2$ 和超声波衰减系数 ${\alpha }_{Ť}$ 显示明显异常 ${乙}^{\star }=28.5$T，被讨论为电子向列转变点。此外，$C_{Ť}$ 表现出低于28.5 T的哈斯-凡·阿尔芬声学振荡。这些弹性异常围绕 ${乙}^{\star }$ 表示四极的电顺序 ${Ø}_{X^2-{ÿ}^2}$ 伴随着 ${乙}_{\mathrm{1个}}G$ 流动性导致的四极-应变耦合导致晶体对称性破坏和费米表面重构 $4F$ 电子与 $p$--$F$ 杂交状态。