Anisotropic inelastic scattering and its interplay with superconductivity in ${\text{URu}}_{2}{\text{Si}}_{2}$

Anisotropic inelastic scattering and its interplay with superconductivity in ${URu}_{2} {Si}_{2}$

Zengwei Zhu, Elena Hassinger, Zhu’an Xu, Dai Aoki, Jacques Flouquet, and Kamran Behnia

Phys. Rev. B 80, 172501 – Published 2 November 2009

Abstract

In contrast to almost all anisotropic superconductors, the upper critical field of ${URu}_{2} {Si}_{2}$ is larger when the field is oriented along the less conducting direction. We present a study of resistivity and Seebeck coefficient extended down to sub-Kelvin temperature range uncovering a singular case of anisotropy. When the current is injected along the $c$ axis ${URu}_{2} {Si}_{2}$ behaves as a low-density Fermi liquid. When it flows along the $a$ axis, even in presence of a large field, resistivity remains T-linear down to $T_{c}$ and the Seebeck coefficient undergoes a sign change at very low temperatures. We conclude that the characteristic energy scale is anisotropic and vanishingly small in the basal plane.