The pressure dependent electrical resistivity of URu$_2$Si$_2$ has been studied at high pressure across the first order phase boundary of $P_x$ where the ground state switches under pressure from "hidden order" (HO) to large moment antiferromagnetic (LAFM) states. The electrical transport in URu$_2$Si$_2$ at low temperatures shows a strong sample dependence. We have measured an ultra-clean single crystal whose quality is the highest among those used in previous studies. The generalized power law ${ \rho}{ \,}={ \,}{ \rho_0}+{ \,}{ A_n}T{ ^n}$ analysis finds that the electric transport property deviates from Fermi liquid theory in the HO phase but obeys the theory well above $P_x$. The analysis using the polynomial in $T$ expression ${ \rho}{ \,}={ \,}{ \rho_0}+{ \,}{ { \alpha}_1}T+{ \,}{ { \alpha}_2}T{ ^2}$ reveals the relation ${ { \alpha}_1}/{ { \alpha}_2}$ $\propto$ $T_{ sc}$ in the HO phase. While the pressure dependence of ${ { \alpha}_2}$ is very weak, ${ { \alpha}_1}$ is roughly proportional to $T_{ sc}$. This suggests a strong correlation between the anomalous quasiparticle scattering and the superconductivity and that both have a common origin. The present study clarifies a universality of the HO phase inherent in strongly correlated electron superconductors near quantum criticality.
Categories: cond-mat.supr-con