Electronic Localization and Two-Dimensional Metallic State in UPt₂Si₂

Abstract

We present a detailed study of the physical properties of single crystalline UPt 2 Si 2 . By neutron diffraction we establish the presence of frozen-in strain disorder on the Pt(2)/Si(2) ligand sites within the tetragonal crystal structure. Further, the system undergoes an antiferromagnetic transition at T N =32 K. In the range T N < T < T irr ≃36 K we observe a cluster glass like phase as result of the disorder. The highly anomalous behavior of the electronic transport properties–metallic along the tetragonal a and localized along the c axis–is a result of the specific type of disorder. Altogether, UPt 2 Si 2 emerges as a model compound to study disorder effects in f electron intermetallics.