The effect of S doping on the superconductivity and nematicity transition of FeSe

In this work, the superconducting properties of FeSe1−xSx with 0 ≤ x ≤ 0.5 were studied. With S doping, Tc is enhanced and shows a dome shape in the studied composition range. XRD measurements demonstrate that S substituting Se sites introduces positive chemical pressure, which can suppress the orbital ordering, manifesting as the decrease of Ts. Hall measurements demonstrate that S doping can effectively tune the charge carriers and make hole-type carriers predominant. However, no maxing Tc is obtained as Ts vanishes in FeSe0.7S0.3, indicating the nematic order has no universal influence on the superconductivity of FeSe system.