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Non-Fermi liquid transport in the vicinity of the nematic quantum critical point of superconducting FeSe1-xSx

W. K. Huang, S. Hosoi, M. Čulo, S. Kasahara, Y. Sato, K. Matsuura, Y. Mizukami, M. Berben, N. E. Hussey, H. Kontani, T. Shibauchi, and Y. Matsuda, Phys. Rev. Research 2, 033367 (2020).

Non-Fermi liquids are strange metals whose physical properties deviate qualitatively from those of conventional metals due to strong quantum fluctuations. In this paper, we report transport measurements on the FeSe1−xSx superconductor, which has a quantum critical point of a nematic order without accompanying antiferromagnetism. We find that in addition to a linear-in-temperature resistivity ρxx∝T, which is close to the Planckian limit, the Hall angle varies as cotθH∝T2 and the low-field magnetoresistance is well scaled as Δρxxxx ∝ tan2θH in the vicinity of the nematic quantum critical point. This set of anomalous charge transport properties show striking resemblance with those reported in cuprate, iron-pnictide, and heavy fermion superconductors, demonstrating that the critical fluctuations of a nematic order with q0 can also lead to a breakdown of the Fermi liquid description.