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

Abstract

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 ρxxa T, which is close to the Planckian limit, the Hall angle varies as cotθHa T2 and the low-field magnetoresistance is well scaled as Δρxx/ρxxa 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 q≈0 can also lead to a breakdown of the Fermi liquid description.