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 ${\rho }_{xx}\propto T$, which is close to the Planckian limit, the Hall angle varies as $\cot {\theta }_{\mathrm{H}}\propto T^2$ and the low-field magnetoresistance is well scaled as $\mathrm{\Delta }{\rho }_{xx}\mathrm{/}{\rho }_{xx}\propto {\tan }^2{\theta }_{\mathrm{H}}$ 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 $\mathbf{q}\approx 0$ can also lead to a breakdown of the Fermi liquid description.