The in-plane resistivity anisotropy is studied in strain-detwinned single crystals of FeSe. In contrast to other iron-based superconductors, FeSe does not develop long-range magnetic order below the tetragonal-to-orthorhombic transition at Ts≈90 K. This allows for the disentanglement of the contributions to the resistivity anisotropy due to nematic and magnetic orders. Comparing direct transport and elastoresistivity measurements, we extract the intrinsic resistivity anisotropy of strain-free samples. The anisotropy peaks slightly below Ts and decreases to nearly zero on cooling down to the superconducting transition. This behavior is consistent with a scenario in which the in-plane resistivity anisotropy is dominated by inelastic scattering by anisotropic spin fluctuations.
Bibliographical noteFunding Information:
We thank V.G. Kogan for useful discussions and A. Sapkota, W.T. Jayasekara, B.G. Ueland, and A.I. Goldman for support of the x-ray diffraction measurement. This work was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences, Materials Science and Engineering Division. The experimental research was performed at Ames Laboratory, which is operated for the U.S. DOE by Iowa State University under Contract No.DE-AC02-07CH11358, and also used resources at the Advanced Photon Source, a U.S. DOE, Office of Science User Facility, operated by Argonne National Laboratory under No.DE-AC02-06CH11357. The theoretical part (R.M.F.) was supported by U.S. DOE under Award No.DE-SC0012336. M.S. acknowledges the support from the Humboldt Foundation. G.D. was funded by the Gordon and Betty Moore Foundation's EPiQS Initiative through Grant No.GBMF4411.