Fig. 3

(Color online) a, b Temperature dependence of in-plane thermopower S(T) for FeSe\(_{1-x}\)S\(_x\). Inset in a shows the dS/dT versus T curves with arrows defining \(T_{\text {hump}}\) and \(T_{\text {min}}\), respectively. c, d The S/T versus T curves at low temperatures with linear fits before \(T_\text {c}\). e, f Temperature dependence of specific heat \(C_\text {p}/T\) vs \(T^2\) with linear fits above \(T_\text {c}\) for FeSe\(_{1-x}\)S\(_x\). g The \(\Delta C_\text {p}/T\) versus T subtracted by the linear fit for the indicated samples. h The \(C_\text {p}/T\) versus \(T^2\) at various fields for FeSe\(_{0.88}\)S\(_{0.12}\). Inset in (h) shows the field induced electronic specific heat \(\Delta \gamma _\text {e}\) versus \(\mu _0 H\) with a fit to the Volovik relation \(\Delta \gamma _\text {e} = A\sqrt{H}\)