Field-induced quadrupolar quantum criticality inPrV2Al20

Abstract

${\mathrm{PrV}}_{2}{\mathrm{Al}}_{20}$ is a heavy-fermion superconductor based on the cubic ${\mathrm{\ensuremath{\Gamma}}}_{3}$ doublet that exhibits nonmagnetic quadrupolar ordering below $\ensuremath{\sim}0.6$ K. Our magnetotransport study on ${\mathrm{PrV}}_{2}{\mathrm{Al}}_{20}$ reveals field-induced quadrupolar quantum criticality at ${\ensuremath{\mu}}_{0}{H}_{\mathrm{c}}\ensuremath{\sim}11$ T applied along the [111] direction. Near the critical field ${\ensuremath{\mu}}_{0}{H}_{\mathrm{c}}$ required to suppress the quadrupolar state, we find a marked enhancement of the resistivity $\ensuremath{\rho}(H,T)$, a divergent quasiparticle effective mass and concomitant non-Fermi-liquid (NFL) behavior [i.e., $\ensuremath{\rho}(T)\ensuremath{\propto}{T}^{n}$ with $n\ensuremath{\le}0.5$]. We also observe the Shubnikov--de Haas effect above ${\ensuremath{\mu}}_{0}{H}_{\mathrm{c}}$, indicating effective mass enhancement or ${m}^{*}/{m}_{0}\ensuremath{\sim}10$. This reveals the competition between the nonmagnetic Kondo effect and the intersite quadrupolar coupling which leads to pronounced NFL behavior in an extensive region of $T$ and ${\ensuremath{\mu}}_{0}H$ emerging from the quantum-critical point.