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arXiv · 2006.03171

Elastoresistance measurements on CaKFe$_4$As$_4$ and KCa$_2$Fe$_4$As$_4$F$_2$ with the Fe site of $C_{2v}$ symmetry

Taichi Terashima·Yoshitaka Matsushita·Hiroyuki Yamase·Naoki Kikugawa·Hideki Abe·Motoharu Imai·Shinya Uji·Shigeyuki Ishida·Hiroshi Eisaki·Akira Iyo·Kunihiro Kihou·Chul-Ho Lee·Teng Wang·Gang Mu
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Abstract

We report resistance and elastoresistance measurements on (Ba$_{0.5}$K$_{0.5}$)Fe$_2$As$_2$, CaKFe$_4$As$_4$, and KCa$_2$Fe$_4$As$_4$F$_2$. The Fe-site symmetry is $D_{2d}$ in the first compound but $C_{2v}$ in the latter two, which lifts the degeneracy of the Fe $d_{xz}$ and $d_{yz}$ orbitals. The temperature dependence of the resistance and elastoresistance is similar between the three compounds. Especially, the [110] elastoresistance is enhanced with decreasing temperature irrespective of the Fe-site symmetry. This appears to be in conflict with recent Raman scattering studies on CaKFe$_4$As$_4$, which suggest the absence of nematic fluctuations. We consider possible ways of reconciliation and suggest that the present result is important in elucidating the origin of in-plane resistivity anisotropy in iron-based superconductors.

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Taichi Terashima, Yoshitaka Matsushita, Hiroyuki Yamase, Naoki Kikugawa, Hideki Abe, Motoharu Imai, Shinya Uji, Shigeyuki Ishida, Hiroshi Eisaki, Akira Iyo, Kunihiro Kihou, Chul-Ho Lee, Teng Wang, Gang Mu. 2020-06-05. Elastoresistance measurements on CaKFe$_4$As$_4$ and KCa$_2$Fe$_4$As$_4$F$_2$ with the Fe site of $C_{2v}$ symmetry. https://doi.org/10.1103/physrevb.102.054511

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