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Non-Fermi liquid transport in the vicinity of nematic quantum critical point of FeSe$_{1-x}$S$_x$ superconductor

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 FeSe$_{1-x}$S$_x$ 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 $ρ_{xx}\propto T$, which is close to the Planckian limit, the Hall angle varies as $\cot θ_{\rm H} \propto T^2$ and the low-field magnetoresistance is well scaled as $Δρ_{xx}/ρ_{xx}\propto \tan^2 θ_{\rm H}$ in the vicinity of the nematic quantum critical point. This set of anomalous charge transport properties shows striking resemblance with those reported in cuprate, iron-pnictide and heavy fermion superconductors, demonstrating that the critical fluctuations of a nematic order with ${\bf q} \approx 0$ can also lead to a breakdown of the Fermi liquid description.