Anomalous transport and magnetotransport of the nematic superconductors FeSe_1-xS_x

A nematic electronic state that breaks the rotational symmetry of the lattice can potentially promote unique conditions for anomalous scattering relevant for superconductivity. Here, we present magnetotransport behaviour of the superconducting FeSe_1−xS_x across a nematic phase transition probed in magnetic fields up to 38T. Inside the nematic phase, the transverse magnetoresistance is very large and anomalous and the Hall coefficient changes sign both as a function of temperature and substitution, beyond the expectation for a two-band model system. A region of linear resistivity is detected inside the nematic phase, where spin fluctuations are present. Near the nematic end point, the resistivity displays a T^3/2 dependence [1,2,3] and the divergent critical fluctuations are suppressed by a finite nematoelastic coupling [2]. We discuss the role played by the high mobility bands and the scattering processes with spin fluctuations, phonos and impurities on the overall magnetotransport behaviour of FeSe_1−xS_x [3]. [1] M. Bristow et al., PRR 2,013309 (2020); [2] P. Reiss et al., Nat. Phys. 16,89 (2020); [3] A.I. Coldea, arXiv:2009.05523.