We report a combined study of in-plane resistivity and thermopower of the pressure-induced heavy-fermion superconductor ${\mathrm{CeAu}}_2{\mathrm{Si}}_2$ up to 27.8 GPa. It is found that thermopower follows a scaling behavior in $T/T^{*}$ almost up to the magnetic critical pressure $p_{\mathrm{c}}\sim 22$ GPa. By comparing with resistivity results, we show that the magnitude and characteristic temperature dependence of thermopower in this pressure range are governed by the Kondo coupling and crystal-field splitting, respectively. Below $p_{\mathrm{c}}$, the superconducting transition is preceded by a large negative thermopower minimum, suggesting a close relationship between the two phenomena. Furthermore, thermopower of a variety of Ce-based Kondo lattices with different crystal structures follows the same scaling relation up to $T/T^{*}\sim 2$.

• Received 2 February 2016
• Revised 30 May 2016

DOI:https://doi.org/10.1103/PhysRevB.94.024522