A Knudsen cell approach for the molecular beam epitaxy of the heavy fermion compound YbRh2Si2

Abstract

Thin films of the heavy fermion compound YbRh2Si2 were grown by molecular beam epitaxy on Ge (001) substrates using effusion cells. As-grown YbRh2Si2 thin films were characterized by a wide range of characterization techniques. X-ray diffraction yields a set of (00l) peaks, demonstrating epitaxial growth along the crystallographic c direction, with a lattice parameter c ranging from 9.84 Å–9.95 Å. The electrical resistivity shows behavior similar to YbRh2Si2 films grown previously using electron-beam evaporators for Rh and Si. The most stoichiometric sample appears to have the highest quality: It has the highest intensity ratio of the YbRh2Si2 (004) diffraction peak to the Ge (004) peak, the highest R(10 K)/R(2.3 K) ratio, a smallest surface roughness, and only a small density of surface defects.