Strong correlation between anomalous quasiparticle scattering and unconventional superconductivity in the hidden-order phase of URu2Si2

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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 ultraclean single crystal whose quality is the highest among those used in previous studies. The generalized power law $\ensuremath{\rho}\phantom{\rule{0.16em}{0ex}}=\phantom{\rule{0.16em}{0ex}}{\ensuremath{\rho}}_{0}+\phantom{\rule{0.16em}{0ex}}{A}_{n}T{}^{n}$ 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 $\ensuremath{\rho}\phantom{\rule{0.16em}{0ex}}=\phantom{\rule{0.16em}{0ex}}{\ensuremath{\rho}}_{0}+\phantom{\rule{0.16em}{0ex}}{\ensuremath{\alpha}}_{1}T+\phantom{\rule{0.16em}{0ex}}{\ensuremath{\alpha}}_{2}T{}^{2}$ reveals the relation ${\ensuremath{\alpha}}_{1}/{\ensuremath{\alpha}}_{2}$ $\ensuremath{\propto}$ ${T}_{\text{sc}}$ in the HO phase. While the pressure dependence of ${\ensuremath{\alpha}}_{2}$ is very weak, ${\ensuremath{\alpha}}_{1}$ is roughly proportional to ${T}_{\text{sc}}$. 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.