Electronic Localization and Two-Dimensional Metallic State in UPt₂Si₂

Abstract

We present a detailed study of the physical properties of single crystalline UPt₂Si₂. 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\\simeq36 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, UPt₂Si₂ emerges as a model compound to study disorder effects in f electron intermetallics.