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

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 ρ_xx ∝ T , which is close to the Planckian limit, the Hall angle varies as cot(θ_H) ∝ T^2 and the low-field magnetoresistance is well scaled as Dρ_xx/ρ_xx ∝ tan^2(θ_H) 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 q ≈ 0 can also lead to a breakdown of the Fermi liquid description.